Yeah, that was what I meant by "upward adjustment".

Sourceforge shows 347K downloads to date.   (288K through May 31; 220K from May 1 to today).

Assuming that there's a 1-to-1 relationship between downloads and users, there's your answer.

http://sourceforge.net/project/stats/?group_id=244765&ugn=bitcoin&type=&mode=alltime

Problems with this metric:

Downward adjustments:
-  Many users have downloaded it to multiple computers.  I account for 3 of those. 
-  Many users downloaded it multiple times to upgrade their version.
   (But with 220K of the downloads being since May 1, I don't think this is a major adjustment)
-  There may be ways to download it via Package installers that don't hit sourceforge.  Not sure.

Upward adjustments:
-  Some users will just use the online wallets, and not download the software.


So my estimate is that there are between 150K and 350K users.
Others may have better estimates.

I think the best approximation of worldwide Bitcoin users might be a factor of the number of forum users there are.  Click on the members tab near the top of this page, and then click the column header twice, that says Date Registered.  This will give you the name of the most recent 30 members of the forum.  Hover over the top name, and you can see that he's number u=18915 (as I write this).

Maybe 5% of Bitcoin users register on the forum, so maybe there are 380K Bitcoin users.


Or another way to look at it:  Look at sourceforge, search for Bitcoin, and see how many people downloaded the software.  79,385 this week.  (you can also see how many over time, but that feature seems to be giving http500 errors at the moment.)  79K downloads in a very strong week.  So maybe 400K downloads all-time.

So your number is probably in the right range.  Definitely bigger than 100K, and probably less than 1M.

No offense intended, but I think many of your slides are far too wordy for a large audience like Defcon.   I think your slides should be bullet points, not complete sentence.  Your oral presentation can fill in all the detail.  

Here's an example of  my suggestion.  Take slide 4.  You have:
Bitcoin Orgins

Baised on a concept called cryptocurrency, first
described in 1998 by Wei Dai on cypherpunks
mailing list.
 -  Work extended by Satoshi Nakamoto in 2009
 -  Satoshi Nakamoto is a mysterious figure no
one knows who he really is.
 -  Appears from nowhere, writes a paper that
solves several major distributed computing
problems in one shot and disapears.

First, two words are misspelled: Based and disappears

Simplified version:

Bitcoin Origins

-  Based on cryptocurrency (1998 cypherpunks mail list)
-  2009 paper by Satoshi Nakamoto
-  Nakamoto is pseudonym and not a public figure
-  Solved several major distributed computing problems

===

Generally, I would think the defcon audience would want to know:
-  Background info (what it is, generally how it works, market size, growth trends)
-  Attack vectors

Personally, I think the attack vector that is the biggest vulnerability and the elephant in the room is the security of the wallet.dat file.  I would think that a room full of people at Defcon (white-hat and black-hat hackers) would be very interested in that attack vector.  How can a hacker install something onto someone's PC that exposes their wallet.dat file?

So I would include a slide or two on that topic.  Specifically:
In the current version of the popular client, wallet.dat contains an unencrypted version of your public and private keys.  100 public keys are generated and stored.  A backup of your wallet.dat file will allow you to recover your current bitcoin balance, plus up to 100 future transactions.  Stealing someone else's wallet.dat file will do the same.  (Personally, I expect that numerous viruses will be written in the next year to expose wallet.dat.  Maybe I'm a pessimist.)

Just my 2 millicoins worth.  (is that the way you say "2 cents worth", in BTC-speak?)

Looks pretty cool.

My eyes aren't so good, and I scanned the first and last several posts for the URL, and it took me a while to see it in your signature.  So to help others, I'll post it:
https://bitoption.org/

I didn't see the commission charge listed anywhere in the FAQ.


So let me make sure I understand this.  You are offering to buy a call for .01 (times 200), and you are looking for someone to write it for you (i.e sell it to you).  Is that about right?  And this means that you'd be able to buy 200 BTC anytime between now and July 28 (presumably 2011) from the writer for $20 each.  

So does the writer need to have 200 BTC on deposit with the exchange?

It does sound like an easy way to pick up 2 BTC!  Because I can buy them for 18 now, move them to the exchange, take your 2 BTC.  Even as a bull, it's a good deal - it just caps my gains on those BTC's at $20.  If only I had 200 BTC!  And if only the system had a bit more reputation!



I can't figure this out.  Please explain.  Do I need to be registered?

Dorphern-

I love it.     Here are a few suggestions.  Please accept them in the spirit intended, or feel free to ignore them.

1.  Consider changing your TITLE tag to be the current USD value, as opposed to Bitval.  Or maybe the current USD value then Bitval.  Example:  {title}17.9984 USD - Bitval {/title}.   And update this with each change.  That way my tab will have the current value in it, while I'm in another tab (in Firefox).

2.  Move your footer down a bit - your Bitcoin donation number is colliding with your history column (in Firefox)

3.  For a memorable name, if you would like a free redirect from myB.TC, let me know, and tell me what shortname to use.  Perhaps myB.TC/current or myB.TC/value.  Of course, you could always buy a domain name from godaddy as well.

How is my logic flawed? 
I am not saying it is a perfect system, but I am saying that it is far easier for me to be sure that there is no virus on a PC on just two occasions - once at the storage to the lockbox and once at the restore from the lockbox, than it is to assure that there is no virus on my PC EVER.

Do others agree that this is a flawed idea?



I believe that Bitcoins will be under attack by virus writers in the coming six months, and that will be a serious blow to their acceptance.  Considering how many zombie PC's are out there as part of botnets, if any one of them gets a wallet.dat file, it'll be stolen.  And, with zero-day vulnerabilities being discovered regularly, I am not willing to risk a large store of my wealth in one place online.

I know personally this is my biggest fear of having a sizable amount of Bitcoins in one place.  I don't fear that they will be worthless or that the crypto will be hacked external to my PC.  I don't worry that my file will get destroyed without a backup.  No, I worry that the PC will get a virus and the file will be copied.

Remember, Bitcoins are never gone from the network.   Even "lost coins" are still in the block chain.


Of course.  Silly of me not to think of that.  That's a much better solution, assuming the file can be small enough.  And a series of QR codes is a much better solution if it doesn't fit into a single one.

The easiest way I know of to print a QR code is to use the Google Graphs URL, but that would obviously introduce a security hole - passing the lockbox codes over the net to Google.  I'll have to check into open source QR code generators - looks like there are several on sourceforge.

I'm thinking about writing a simple client whose purpose would be to help facilitate a large money storage area - a lock box. 

The concept is to take large quantities of Bitcoins and dump them offline where they can be stored onto (gasp) paper.  Paper has some benefits for wealth storage.  I don't have to worry about viruses.  It's not "easy" for someone remotely to steal a copy, etc.


The software would behave like this:

1) When you run it, the program creates a new wallet key pair.  Not 100 like the current client, but just one (or as few as necessary).
2) It creates a new wallet file, with a name different from wallet.dat, containing public and private keys.  Let's call it lockbox.dat.  The idea is that this is a MINIMAL file - as small as possible.
3) It connects to the bitcoin network like all other clients.
4) You can transfer funds to this wallet (or lockbox) using your normal client.
5) You can print out the contents of the lockbox file in Hex or other readable characters.
6) You can select a function named  "shred" or "destroy" - which, after confirmation that you really want to do this, overwrites your lockbox.dat file with random zeros and ones.  You now have only the printed copy of your lockbox file - no electronic version.
7) You can select "recreate", which allows you to type in your lockbox file to get your money into electronic form again.



Is there any value in this?   I think I can do it by modifying the current client to eliminate a lot of the current functionality, and add in a few simple functions listed above.

Any suggestions for improvement?  Should this be a feature of the current client, or a separate program?

I found the first snapshot of Mt.Gox's website to be pretty interesting.  Thought you might enjoy:

http://web.archive.org/web/20070525044536/http://mtgox.com/gwt/mtgox.php

I saw a post for shortco.in (a great idea), and I just wanted to remind folks that myB.TC has short URLs for you to put your wallet ID in a public place.

edit:  Chatter removed.

San Francisco Examiner: http://www.sfexaminer.com/opinion/daily-outrage/2011/06/supermarket-illegal-drugs-pops-internet

Naaah.  When grandparents read about it in AARP magazine or Reader's Digest, then it's mainstream.
When you can walk down the street and ask ten people if they've heard of Bitcoin, nine people have.  Then it's mainstream.

This is a huge milestone, but there's room to grow until Bitcoin is as much a recognized word as "Facebook".
Then I'd say it's speculative value has peaked.  Then we move to utility value.

All yours.  Good till at least 2013....  http://myb.tc/foo/

Thanks again!

Gravatar - great idea.
OpenID login 404:  I think I fixed just now.


I really appreciate the bug report.  Let me know if you want the short name "foo", and I'll hook you up with it.  (For now, I've disabled registering 3-letter short names, but it's the least I can do for your bug report and idea.)  Set up an account, and I'll assign you "฿foo" (if you want it)

Yeah, the guy who claimed Bitcoin was a scam and doomed to fail will be bragging about how right he was, and saying "see, I told ya so!", when the price of bitcoins "plummets" from $160 per BTC to $147/BTC.

What's interesting to me is to think of what is going to happen when Wall Street Investors start rushing in to "get a piece of the action".
I think this is barely starting to happen now, but will go strong for the next few months.


Throwing ten grand at a high-risk idea is nothing to some of these guys.  Especially if it's a hedge against all other things that they are invested in (like the traditional money, currency, and the banking system in general).


The irony here is that these same "bankers and investors" could totally drive the price of Bitcoins up.  You will be rejoicing at the rise in value as they join the Bitcoin party.  People hope that Bitcoin destroys "them" (or their ways), yet celebrate when they buy in.  That just feels odd to me.

Yeah, you just have to make sure that your "claim" appears on the page that you are submitting to the website.  My website only checks the one webpage that is submitted.

Hey bitboy, thanks for the donation.  Really appreciate it.
By the way you have a minor typo on your personal Bitcoin webpage:      ฿bitboy


"Here's my Bitcoin Address. Thank for visiting."     (You might want "Thank" to be "Thanks" or "Thank you")

I manually assigned it to you, Xenland.

The issue was that your claim needs to be YOUR first message on the webpage.  Technically, I'm doing a regular expression, looking for your name at the beginning of a post, and the verification code, and making sure that there are no other "beginning of posts" in that match.    I'm struggling to figure out a Regular Expression that works exactly right.  Unfortunately it was finding your first post, and then later on the page (but not in the same post), your verification code.  I'm still working to improve that.  Sorry!


The work around is to make sure that you pick a forum topic that you haven't posted on, and claim it there.

Thank you.

You need to request it on the site, and the site will walk you through the claim process (giving you a code=xxxxx to post.)
Let me know if it's not self explanatory.

I like the photo idea, and am working on it.  I'm torn between several different concepts.  Let me know your opinion:

1.  Let users link to a single external photo or image.  This is easy.  Issues:  how do I size it (or do I?), and do I need to worry about some clown linking to an obscene image?

2.  Let users upload profile images.  This is slightly harder, but pretty easy. 

3.  Let users design a background image and a profile pic, like Twitter's page.  This might be an overkill.



Opinions?