I think it's a good analogy, which makes the issue easier to understand. If there are flaws in the analogy, I'm happy to discuss them. The criticism of AlexGR that people on a bus are real, and Bitcoin transactions in a block (according to him) are not, is just childish.
His other remark that it's cheap to buy all the space in a block (because blocks are quite small and transactions cheap), doesn't discredit the analogy. If someone wants to take out the high speed train from Amsterdam to Paris, he can buy all the train tickets. It's doable, and effectively a DOS attack preventing any other people from using the train. If anything, it shows my analogy is a correct one.
Not there yet.
When you broadcast a tx, where you "pay", say, 1 satoshi per byte, what you are *really* doing is that you are stating your intention that if you get included in some block then you will pay the said amount.
You don't actually pay anything beforehand. The payment is only done upon inclusion. If you get the service, you get paid. If someone else pays more than you, then HE gets it, not you. In that scenario, where he got in and you didn't, the only party paying is him, not you. You haven't paid anything. You only said that you were willing to pay a trivial amount, which was less than him, and the miner said ok, you aren't paying me that much, so I'm going to process that other guy who pays me more.
I can imagine that a flood of tx without fee can be considered spam. But nowadays, only mining pools use zero fee tx to payout their miners. There are hardly any zero fee tx issued otherwise. (800 in the past 24 hours, source:
https://bitcoinfees.21.co/ ) But if a tx carries a fee, how to decide if it's spam or not? What is your definition of spam?
Likewise, remember, you haven't paid anything until inclusion. You are just broadcasting your intentions, for free.
In this sense, broadcasting a billion txs and "paying a fee" of 1 satoshi/byte doesn't mean anything. The broadcasting of this billion txs is free. If a few thousands of these txs go in, if at all, I may have to pay 1 satoshi/byte.
This is precisely why the mempool backlog is a useless metric. It could be 50 gigabytes of backlogged txs, which even the sender isn't really expecting to get included.
Personally, I'm not anxious for all that spam to be "cleared" by getting included in the blockchain.
It would be like having the street outside your house filled with trash and considering collecting them inside your house to "clean the street".
Nice analogy, it illustrates how we disagree. Going with the trash theme, IMO the current setup is akin to saying everything people throw away should be dumped and never touched again. Never mind that due to changing market conditions and innovation, some trash may actually be valuable to people if they can get their hands on it - recycling metals for example.
If you remove, by dictate, the ability to process "trash" beyond some arbitrary treshold, you remove the markets ability to correctly value that "trash".
Well, physical garbage do tend to have more valuable stuff in them compared to digital...
Anyway, in the above analogy, the street garbage is the mempool, and your house is the blockchain. Now, the mempool can be spammed A LOT because it is practically free to do so (broadcasting intentions to get included, either for free, or with a trivial fee) and you can decide whether you will do what the spammer wants, or not.
The market always has an ability to value the trash: If the sender of the tx doesn't care for his tx (broadcasting zero and near-zero cost txs) he is betraying his intentions. When you see "blocks are full" and fees topping out at 4-5-6 cents for 1st block inclusion, without activating any serious fee competition, you know right away what is going on: Junk transactions are flowing in.
If, say, I want to send my coins to an exchange and sell right away there are various costs:
-Exchange commissions
-Bank wire/withdrawal costs
-Conversion fees (for non-$ users)
...which might add up to tens of dollars. Now why would I be "cheap" when I'm sending the tx?... to save what? 0.03$?
Poll
