More useful-looking code:

https://bitbucket.org/blueluna/transmission_supervisor/wiki/Home

http://www.oneswarm.org/about.html

http://en.wikipedia.org/wiki/Opentracker


I am wondering how much of an advertising budget folks looking to sell storage space are willing to spend to find customers for such a service; what percentage of gross earnings will it take to maintain a given level of gross earnings or even increase gross earnings? What percent commissions should people who actually manage to bring a paying customer get, and should it be only a percentage of the actual payment they convince the customer to make instead of an on-going percent, so that salespeople will be motivated to keep in touch with customers encouraging them to renew when their initial payment has been exhausted?

It is all very well to say lets bring those looking for money together with those who have money and want to spend it, but the competition these days for people who even merely have money or might have money, let alone are actually willing to spend it, has gotten a lot more intense, and more expensive, than back in the gravy-train raining-soup days of the very very late twentieth century.

Thus budgeting for purchase of marketing from outsiders (buying adsense ads facebook ads and so on conceivably, maintaining email capture landing-pages and professional third party mailing-list services, purchase of raw hits, etc etc etc), and/or actual marketing by insiders - surfing manual-surf traffic-exchanges? Running auto-surfs in browsers 24/7? Or merely contributing money to pay for professional marketing?

I guess the implication here is am not seeing a whole lot of "heck yes I'll buy X gigabytes a month at Y bitcoins a month per gigabyte" type of comments so I am dubious of finding much paying demand.

Reverting to the Treasure Map model was largely because of having that impression; I had drifted toward lets see who is still online in a few months of freely sharing and see how many months consistent reliable storage hosts will end up having to be online before starting to see people actually offering money instead of merely offering storage of their own. I have also, y'see, an impression that people are more willing to offer storage than to offer money thus if they are reluctant to even make their storage available it is even less likely they will ever actually make any of their money available.

Maybe those with bitcoins can demonstrate control of addresses with bitcoins in them for a few months to show they not only have coin but are disciplined enough to still have coin a month or few down the line, while those who have space can demonstrate they not only have space but it can be utilised and still has in it in a month or few what was entrusted to it, then maybe we can get a better idea of whether this is going to be a workable matchmaking project?

Bearing in mind that if we can do this with off the rack software and already existing networks which might have "network effects" of their own already, the potential paying customers might well notice that what we have come up with could probably work sufficiently well without paying any actual money. Afterall look at the numbers of people doing bitswarming already, each "seeder" providing storage already if only while their own downloading is happening.

The only example we have encountered so far of someone who actually needs space but has none to offer turns out to be probably better served by begging borrowing or stealing a spare disk drive from her brother, so is not actually a case study in favour of this project afterall...

Maybe in reality most use-cases of wanting/needing off-site storage tend to be not really for storage at all but actually for sharing (with oneself and/or others), the desire to get the data off the site being to have it somewhere all one's friends can look at it and enjoy it and so on, you oneself can access it from anywhere and so on, thus maybe tend to be more about bandwidth in a way than storage?

Maybe those looking to make money with their storage capacity would be best off  stocking it with content many people want but not quite enough people for that specific content to already be 24/7 available for free?

-MarkM-

Oh gosh, he made you read further to find out something you wanted to know?

Gosh, Real Marketers don't do stuff like that, do they?

-MarkM- (maybe they do, read on to explore in more depth the fascinating contrast(s) between journalism and copywriting...)

It had been quite a while since last I had read up in Bittorrent, so I am wikipeding it now.

Take a look at http://burnbit.com/

Looks handy for anyone who can upload their file to their website to have their website be their initial-seed host.

I remember this part:

"Routers that use network address translation (NAT) must maintain tables of source and destination IP addresses and ports. Typical home routers are limited to about 2000 table entries[citation needed] while some more expensive routers have larger table capacities. BitTorrent frequently contacts 20–30 servers per second, rapidly filling the NAT tables. This is a common cause of home routers locking up.[42]"

DIstributed key word search sounds interesting and there is  free open source code for it (see for example Tribler).

Maybe we don't need any centralisation at all. Adding money into the equation might be do-able just with a Treasure Hunt script, on top of which some GUI-lover can put a GUI, and a Bury Treasure script likewise which an initial-seeder (person hoping to get copies of a file to persist a while out in torrentland) can use to bury treasure in a file before initial seeding and to advertise a treasure map some time later.

("By the way dutiful retainers of my data, if you take a look at bytes X through Y, you might recognise that there, but for ROT13, is a bitcoin private key. Those of you who know not what ROT13 might signify are welcome to await my next clue, or, if impatient, to perform some research on the topic...")

-MarkM-

Content-Addressable Storage (CAS) uses the content to address storage not the location in the world or on disk or whatever at which it is stored nor some nickname some user might find humanly appropriate characterising the file or its content.

This, any change in the content of a block / unit/ file / whatever of storage changes the identity/ID of that block /unit/ file / whatever.

Basically the hash is what one refers to it by, so anything that does not hash to the hash that was requested is not what was requested.

Doing this block by block instead of file means that any block can be requested.

Many systems work this way, including, I think, Freenet, Tahoe-LAFS, GNUnet, Twisted Storage, and camlistore. Maybe even bittorrent. If your bittorrent does not offer you a user-interface for asking for individual blocks or sectors or fragments or somesuch of a file, likely it is merely hiding that functionality from you the poor ignorant human, while using it itself to request specific portions of a file from specific hosts in order to download many portions at once from many hosts.

So maybe you just have to dig a little deeper into some kind of advanced mode or debug mode of your client, or complain to its developers that the user-interface is somehow not making clear to you how to tell it yourself which piece to get from where.

-MarkM-

Ok, so service.com is the cluster co-ordinator for a bunch of storage nodes, or maybe is even further up a hierarchy than that.

How does the customer know how many copies of his/her file are seeded? Specifically, are storage.com's claims about that believed or does the customer get to see directly peer to peer with the hosts hosting the copies that they claim to be seeding it?

I ask because I am wondering if each host can add a firstbits string to the name by which they seed a copy.

For example say you want to store SgtSpike-Desktop-2012-05-31.bak.rar

I have a firstbits of 1DIgitalis, so I seed it as SgtSpike-Desktop-2012-05-31.bak.rar.1DIgitalis or whatever: basically I put my firstbits in there, or if filename length isn't a problem, then lets forget firstbits and use full bitcoin-addresses.

Now you should be able to ask bittorrent for a list of all files whose name start with SgtSpike? or maybe for any with keywords of SgtSpike and Desktop? Or if wondering what else I am hosting, all files with 1Digitalis in the name, or something like that?

Or does bittorrent have metadata even, like GNUnet and hmm not sure but I think maybe Tahoe-LAFS do, so a seeder can associate a whole bunch of keywords with a file without having to stuff them into the filename?

I am thinking here maybe we could eliminate service.com entirely even, simply by including in the keywords or filenames the offered reward for seeders from some offering seeder, the identity of the offering seeder, and the bitcoin address to which to send rewards for the copy having this name or keywords-set (description?)

Service.com could be useful as escrow though, so storage nodes do not have to trust some random seeder's offer just storage.com's claim that storage.com will make the offer good.

-MarkM-

Thank you! Okay, I now agree that bittorrent is a strong candidate.

Quite a few other systems can split the load and also migrate blocks towards regions where those blocks are popular though, which I have not heard of bittorrent doing. My impression has been that with bittorrent you deal with an entire file at a time, so any host that has the file has the file?

And the only migration in response to regional/directional demand is when someone not only downloads the file but also chooses to make downloaded files available for others to get from them?

Actually, can you even have all downloads automatically seeded for others to get from you, or do you (at least with whatever client it is that makes you feel so sure everyone already knows how to use it) have to explicitly pick from among your downloads specific files on a case by case basis that you want to "seed" for others to retrieve from you?

Block by block storage could let more people get in on the money even when the paying customer only wants a few copies. Some kind of RAID type system or even the Nimbus.io system could split the data up in such a way that X out of N nodes would have to die to cause loss of data. We could make some copies be full copies, putting all the blocks of a file on one host - all its eggs in one basket - and then also have some scattered-blocks copies also to share the wealth, basically trying to make sure all our storage-providers get at least some token amount of data to store.

The migration features of some distributed storage systems could also provide trickles for people who are along the way toward regions where a particular file is most popular, as blocks migrate toward the region where they are in high demand.

However okay if bittorrent already provides some of that stuff, by being able to automatically make available anything a node downloads, lets move on for now until I look again more closely at the distributed storage systems that do resemble bittorrent in those ways.

So, the money. Well, disk quotas still are on the table as a means by which someone providing space can limit the amount of space they are providing, if for some reason bittorrent does not already include setting how much disk space mximum you wish it to use. How does bittorrent know who is using how much space though? Maybe we need to look at bittorrent server software which google shows plenty of. Maybe if you run a bittorrent server instead of just a client, you will find it lets you allocate space to various users and stuff like that?

If bittorrent does not maintain some kind of concept of which users are using how much space, does it even maintain some concept of users at all, associating each file with a user?

If not you might have to run one instance per user whose usage you wish to account separately.

I am thus starting to suspect that instead of a peer to peer storage-node model we might have to go for a peer to peer cluster model, in which storage nodes only have one customer, which is their cluster co-ordinator node. Normal people who just want to sell some space could deal directly with their nearest cluster-coordinator or pick some other hopefully not too distant cluster co-ordinator.

We then don't need to worry about normal home-user types having to deal with complicated issues, they can simply try to set up a link of some kind with their chosen cluster-coordinator  and see if they notice enough satoshis coming in at the end of each month to motivate them to stick it out another month or even maybe to do some marketing of the service to try to bring in some customers.

-MarkM-

EDIT: Maybe since security has come up we should from the get-go assume storage nodes will be virtual machines, anyone wanting to be a storage node simply fires up some standard virtual machine specific to the purpose? That gives them a disk space max and CPU usage max right off the bat without having to get into granular by user/group usage quota systems.

Okay, so you have local area network sharing but are concerned about its security.

This many years or decades in has it not by now been given an option to encrypt the data on the wire?

If not, then a Virtual Private Network might be required, to set up host and customer with a private local area that happens to extend across the internet. That might well *not* be already right there on your system setup menus/icons on Windows. For Linux there are lots of them, I would ask my package manager aka installer to search then try to choose which one to actually use somehow maybe partly by whether it seems one I have heard of a lot or seems to be the usual vanilla standard or whatever... Aha I see "OpenVPN", the "Open" part has me sold on it at first sight.

Google WIndows VPN:

Configure a VPN Connection Using Windows XP
www.windowsecurity.com/.../configure-vpn-connection-windows-xp...
18 Mar 2005 – In this article we will learn how to configure a connection to a virtual private network (VPN) using Windows XP. This article will show you how to ...

Google goes on list other flavours of WIndows. (Link above is an error 404 but hey, back in 2005 with Windows XP this stuff already existed.)

For disk quotas googling "Windows disk quota" shows immediate results for various windows 2000+, windows server, and windows 7 systems, one might have to dig deeper for older systems and they might well have deliberately tried to keep such "professional" features out of old cheap home-user versions intended to lure professionals into upgrading.

But, okay, that is more suitable to you and your sister than to random strangers, whom you of course wisely do NOT want on your local area/net.

If Bittorrent already does what you want then great. If not I still do not really understand the fascination of it, because previously you have been writing about having one to three hosts host the customer's data. If the goal is to have hundreds or thousands or hundreds of thousands of hosts host it, then yes, I too would look at torrent technology. But for the probably for our purposes more common case of 1 to 99 hosts, with 1 to 25 or less likely far more common, I am not convinced of a need to resort to torrent.

-MarkM-

Windows Shares, or SAMBA, or whatever such capabilities are now called in Windows, existed in Windows 3-point-something or earlier.

What operating system are you using / used-to?

What operating system is your sister using / used-to?

I am talking about built in stuff that should be right in your system setup menus/icons somewhere already just waiting for you to turn it on, or in the case of Linux distributions conceivably for you to click on in the install packages tool to have them installed for you.

Certainly far more normal and standard that strange third-party stuff such as bittorrent or retroshare or whatever. It is native to the system / distribution / operating-system.

-MarkM-

Okay well also consider that even Windows users might already have as part of Windows something called something along the lines of Windows Shares, or SAMBA shares, or something like that, which should be able to provide them the ability to specify directories they would like others to be able to share, and to mount other people's such directories so they can just drag and drop stuff. The shared directories are "actually" shared, at least once they are mounted.

In Unix type systems, maybe including OS/X, there is a pretty standard remote mount system (NFS: Network File System) that lets you similarly make directories available for remote mounting, though how exactly you tell it who gets access and how is somewhat different.

There is (or certainly long ago used to be) SAMBA code for Unix type systems so that for example an ISP could offer Windows users mountable home-directories on the ISP's unix/linux/etc based servers.

Hosts that are Linux based even have available quota systems so they can assign quotas to users, and have 'cron' scheduling daemon that runs things on specified schedules. Such hosts could have cron run a script that looks up for each user a bitcoin account the balance of which will be used as the number of units of storage to set that user's quota to, and another, monthly script that deducts bitcoins from that account based on the maximum amount of storage that user had actually used in the last month.

Presumably "we" need not worry about what people who want to sell space would prefer in the way of software to be such a seller, except in proportion to the number of bitcoins they offer as bounty for each specific script or function etc they specify? Folk who can handle the technical stuff themselves can get up and running selling space to bring in coins first, limited possibly by the need for pretty front ends for the buyers of space to use in order to maximise the coins brought in by/to the project; then over time as the sellers find it worth their coins to have prettier software for their end made such software will or will not get made.

Basically if software is to be developed we want first to have coin in hand with which to motivate software developers to develop it?

Meanwhile those who are able to raise coin by setting up as sellers using existing software can attack the problem of what exactly do the people who want to buy space need (other than coin) in order to be able to buy it? Such as ability to tell their operating system to make available one or more directories as "shares"? Coupled possibly with the ability to tell their router to allow people coming in from the net looking for shares/specific-shares to reach which port of which machine to get those shares?

-MarkM-

You could sign, using a bitcoin client, a message to your sister claiming that your machine and the bitcoin address used to sign the message are owned/controlled by the same person/company.

However, does she even get told who asked for her files? And if she displays a list of what files you have on your end is your machine identified similarly to the way it is identified in her logs of who has downloaded which of her files?

Since IP addresses are not usually stable for many home users, does bittorrent have some kind of node-identity that it uses for such identifications/logs?

When you download a file from her, can you be configured at your end such that what you downloaded is automatically also then available to be downloaded from you?

-MarkM-

Hmm, I get the impression it is more like multiple hosts take the data than you give the data to multiple hosts, in the sense that it is pull not push. You can't really just give them the data, you have to somehow cause them to ask you for it?

A push could be useful for cases like you go away for the weekend but your sister still has photos she wants to move or copy to you.

If you can set up an automated pull though that will keep asking her for anything new, that would be fine.

Or maybe you could search for specific filenames, leaving the search constantly running, so any time fridays.batch.zip becomes available your client will grab it, as soon as saturdays.batch.zip becomes available it will grab that too and so on, so she has list of names she can zip a batch as to have your machine grab them even while you are away from keyboard.

-MarkM-

I wasn't the one who brought torrent into this. The thread seemed to diverge between offsite copies of data, actually moving data offsite no longer having it onsite, and whether anyone other than its "seeder" / "publisher" / "uploader" ... (owner, even?) ... might want a copy too, which seems to be the usual use-case for Torrent. (Because Torrent is designed for getting the same data to many many people aka to optimise having many many people all wanting the same data and not having a copy of it themselves already.)


As you also mentioned earlier having an entire drive free, maybe just sending her that drive to install in her machine would be a good way to tide her over her diskspace-crunch? Or, have her upload her photos to you? Or, download them from her?


See, Torrent comes up again. I do not yet see why Torrent. Maybe though it is because of the front end GUI, not what the actual protocol it uses it optimised for?

Can you have your sister install torrent and seed a directory so you can download that directory from her any time you wish, then cryptozip or whatever the photos at risk and put them into that directory for you to grab?

Or, how about RetroShare? About the only thing going for RetroShare seems to be eye-candy GUI, presumably it should be just as GUI-user friendly as Torrent?

I have never used Torrent though doubtless can find code for it that will work on Linux. In fact I have on my GUI menus something called Transmission BitTorrent Client. If I used that to grab files from you, would you be able to grab them back from me? Or would I need a server rather than a client for you to be able to grab from me? I really know very little about Torrent.

-MarkM-

I think it started from an ambiguity about whether we are talking about back-up storage or primary storage.

By that I mean there is a lot of difference between storing a just-in-case copy of your infinitely valuable irreplaceable data and storing your actual infinitely valuable irreplaceable data.

The case of a sister running out of space for photographs for example sounded as if the plan would be that she "move" photographs to offsite storage rather than that she "copy" them (copy implying she of course still has it herself, she does not delete from her system when she copies to someone else's) to offsite storage.

These are very very very very - it is hard to understate how very - different cases.

One must always act as if each and every piece of media on which your data resides is a diabolically patient, fiendish enemy, always hoping to find itself in the position of being the only surviving copy of the data so that it can strike at you as no other copy up until that moment could do, by maliciously destroying the only copy of your data.

This applies to backups more even than to the files backed up, because if you lose the files you have backups of, you can simply restore from backups. But if the backups are lost or corrupt, that is when you really need backups.

So always back up your backups, as if they are hoping and hoping and hoping you will need them so they can nyah nyah nyah you by failing you.

The idea that someone's sister might give me her precious files without keeping a copy herself made me very very worried about how sure I could be that I would still have them when she actually needs them.


Maybe we can do some trials/tests between us then, trading onsite to offsite storage, and see how it goes?

-MarkM-

There are bitcoin-exchanges in which users pick and choose which offer(s) to accept instead of being matched by the market-operator; off-hand I have the impression they tend to also require the users to then conduct the trade out of band between themselves, thus losing the assurance of delivery by both parties that automatic-match exchanges such as MtGox provide.

You brought up the idea of there being these two different approaches available, I merely tried to respond, mostly by elaborating the implications.

It seems to me that it would be useful to take it that one choice opens up questions as to whether the product is a commodity at all, due to seeming to at least potentially bring the product's fungibility into question.

One might for example avoid picking offers that involve coins trackable back on their blockchain to some theft break-in heist scam etc. I have read various threads in which various people assert that such distinctions challenge the very fungibility of blockchain-based coins.

Maybe both types of "market" are useful and we should have both.

Certainly so far I am in picking and choosing mode, still seeking specific individuals with whom I might consider trading; albeit I am also considering trading offsite for onsite initially too, keeping it all about the product - the possibly-a-commodity item - without having to worry yet about (possibly non-fungible?) money/currency trade.

Maybe part of the picking and choosing would  be which providers of the "commodity" actually seem over time to be providing an actual "commodity" rather than a product not quite exactly like (co-fungible with?) the supposed "commodity" we could end up going on to create a "commodity market" for?

-MarkM-

My game-players have always wanted to be able to choose which offer to accept, but it does open new "game the system" opportunities. Specifically, volume can be created at high prices between sock-puppets (or, in general, colluders) without any non-sockpuppet bids/offers being accepted.

The ostensible reasons and/or excuses for wanting such a structure tend to be not wanting to buy stuff from enemies, wanting to offer allies better prices than offered to enemies and neutrals, and preferring reliable suppliers or suppliers favoured for the quality of the actual "commodity" provided. (Which goes against the idea that to be a "commodity" a product should be fungible.)


Transferring it to another block server is getting into more complex transactions, but whether the client is paying for delivery to client plus deletion from the provider or just delivery to the client seems a useful distinction. Though it does bring up the corner case or imaginary case of how about the client only wants it deleted from the provider (a takedown request) without the bandwidth overhead of taking delivery of a copy.


This is another form or arising of the "is this really a commodity, since commodities should be fungible" problem.

-MarkM-

I hesitated to suggest DeVCoins on reading it was on WIndows, partly due to not recalling offhand who exactly had seemed to have trouble setting up devcoind on Windows. But once you are on Linux, running devcoind should not be very difficult. (I do not know how difficult adding another chain to ABE might be but since you offered...)

Of course it would be lovely to also see GRouPcoin there, but maybe you are more interested in appealing to existing levels of interest in chains than in possibly finding more interest is aroused by your adding the chain than seemed to exist before you added the chain. (More people might hear of it for the first time by seeing it there than already know of its existence through other channels?)

-MarkM-

I am curious where you people put your offsite backups, and how.

It would be interesting to know not only for ideas I might apply to my own offsite backup strategies and/or tactics but also simply to assure me you are serious about data integrity / safety in the first place.

Meanwhile with this torrent type stuff continuing to come up I am thinking again of actual-block-of-data markets.

If satoshis are small enough units of value then maybe the markets can use satoshis as units of value to use to bid on such markets, if not then some lower value per coin flavour of coin might be better, or some other kind of microsatoshi or millisatoshi scale unit of value.

You seem to be more interested in bitcoins or satoshis than in whatever you might be able to provide in return, so lets drive this from the bitcoin or satoshi or other coin side.

I offer to buy a block of data whose hash is $H, and solicit bids as to how many microsatoshis that specific block is currently available for.

If anyone does have that block of data, great, I'll either buy it or await a better price.

For my personal current application-of-interest, I actually already have that block myself anyway, so I can also offer it myself, possibly at a lower price than the offers I am seeing from others. (Because, it is a block of a backup of data of mine, and I already made and retained a copy of that backup myself.)

Someone else might be interested in buying the block whose hash is $D, and bid higher for that block than I typically bid for blocks of my backups. (Possibly because block $D contains part of a particularly appealing frame of a particularly popular scene of "Dolly Does Dallas XII", not yet out in theatres and DVD stores but reported to have been leaked to the internetz.)

Lots of people might be bidding to buy block $D simply on speculation, figuring that once they have collected enough blocks of that frame of that movie they will be able to resell entire frames or maybe entire clips on other markets.

Torrent end-users might not even be up to date enough on current internetz affairs to even know of this market in blocks of data, they might be eagerly waiting for their favourite torrent-provider to offer a full copy of the entire movie, having no idea of this back room market in blocks between torrent-providers and others whereby such people manage to lay their hands, block by block, on such hot digital assets...

-MarkM-

This is again going so far out into in the vapourware domain that now as a person actually looking to store some data offsite, but not needing yet anywhere near a terrabyte nor even, yet, 100 gigabytes, I am back to thinking Freenet is the way to go for at least one copy at the present stage in the discussion.

Right now I am not yet sure if one gigabyte would suffice, but think it quite likely that five gigabytes might, for a possibly short period of time depending on how fast my Open Transactions server aquires actual users doing real transactions.

So right now I am thinking of putting backups on whatever free five gigs for life offers I can use from Linux plus test trying to send a copy, as a modifiable file so replacing it doesn't double the storage requirements, to Freenet to see if once there it can actually be gotten back and if so for how long.

Since freenet has friend-to-friend modes available, possibly I could find some other people looking to start with one to five gigabytes or so, set up friend to friend links with them, and see how that works out for a while as a mutual swap, since my problem is not lack of onsite space but desire to swap onsite space for offsite space.

I also have GNUnet and Tahoe-LAFS installed. (Also Tor and i2p, but they are transport more than storage.)

So, are there any among you who are looking to swap onsite for offsite space?

(We can worry about selling space later, once having mutually assured ourselves there is actually space and that it is actually useable and reliable over some reasonably long term.)

-MarkM-

EDIT: Friend to friend might not even be ideal, if it opens the possibility of being someone's only link to the freenet / GNUnet / Tahoe-LAFS grid / whatever; it might suffice to simply request each other's files while both being on such a net.?.?

EDIT2: Technically, I actually also have RetroShare, I just happen not to bother running it lately due to lack of connections.

Oh sorry did I type the wrong SHA-number? If so sorry, typo.

-MarkM-

That sounds like an argument in favour of dropping a block once it has been "verified", as then the host knows it will only be downloaded once, either by the "verifying host" or by the actual customer. That would also bring back paying more for more copies, because unless the customer specified, and paid for, two copies there would just be one copy of each block floating around (probably plus one insurance copy the market/escrow has in escrow) unless the customer paid to have it downloaded twice, in which case after it has been "verified" the host who had it could keep it, waiting for a second download.

However since your argument is basically a storage-provider-side reason why the provider might want to drop off the list of hosts the block is available from we might as well leave it to them to choose for themselves whether they want to drop the block due to having already spent quite enough bandwidth on that block.


Hmm, I am not really very familiar with that. But if it offers us a market for our service by all means lets explore that.

Usually torrenting tends to imagine the blocks are going to be sought by more people than just the original uploader, right? So hey, if there is a wider market for blocks than merely selling them back to their uploader, and the uploader is willing to provide keys for decrypting the data either to our system / the storage providers (to enable selling the data in useful form) or to other end-users (in order to make the uploader some money to cover the cost of having our system store the blocks), great. More money for the service and maybe also for the uploader(s).

-MarkM-

EDIT: Also, if providers do not know until later whether thousands of people are suddenly going to offer to buy copies of certain blocks, holding some on speculation might be encouraged, since any block might turn out upon release of decryption keys of the file it is a block of to be very popular / in demand.

EDIT2: We could go even further, constructing files whose decryption does not require all previous blocks to decrypt a block, so that someday keys can be released for any specific block, revealing that specific block to be very valuable / popular in some way.

EDIT3: For example we could habitually insert into our files a block containing a bitcoin privkey. Someday, maybe quite some time after the pool-hopper types have long forgotten that block, we could release a key allowing anyone who retained that block on spec to decrypt it and get those bitcoins...

EDIT4: We could also have lotteries, such that each time a bitcoin blockchain block reaches a depth of 120 some deterministic function computes some number of what could maybe happen to be block-hashes, or certain numbers of bytes of some block-hashes with the number of matching bytes being related to some lottery-winnings-distribution setup... If, of course, one does in fact still have a data-block that is at least 120 blockchain block-cycles old that matches...