Quote from: ShireSilver on May 18, 2013, 03:58:24 PM

Quote from: scintill on May 17, 2013, 09:38:03 PM

d) this change is trying to prevent the sending of amounts so small it costs more to spend them than they are worth (how is it sane to want to keep this property?!).

Who decides what a transaction is worth? Value is subjective, and even if you can't think of a reason why someone might be willing to pay a lot to send a transaction that doesn't mean they don't exist.

The fees do. Lets say the only way to spend USD was to mail them to a recipient. A stamp costs $0.46 obviously paying $0.47 ($0.01 + $0.46) to make a $0.01 payment is UNECONOMICAL. The fact that you could make a $0.01 payment (literally mail a US penny to a creditor) doesn't change the fact that it is UNECONOMICAL. Right now transactions below ~5000 satoshis are uneconomical. They won't be spent because the cost to spend them is greater than the value gained in spending them.

In the future (if/when exchange rate rises significantly) the threshold on economic transactions will decline. That is all "dust" is. Dust is the threshold where an output isn't economical to spend. Prior it 0.8.2 you could create outputs that due to economics likely would never be spent after 0.8.2 you can't. Remember the dust threshold is now a variable. The default value makes it 5430 satoshis however miners are free to set it to whatever they want.

Miners have an incentive to both:
a) not exclude economical (meaning will be respent in the future) transactions because that would be turning away paying customers
AND
b) exclude non-economical transactions as they bloat the UXTO and raise miner's costs perpetually.

Thus miners have no incentive to set the dust threshold incorrectly. Too high means less revenue and too low means excessive future cost. 0.8.2 lays the foundation for a more comprehensive system to balance the needs of small transactions with the cost paid by everyone

There is cost to bitcoin, there will ALWAYS be a cost to Bitcoin. Now today that cost is partially "hidden" because the block subsidy is so large but the cost still exists. Bitcoin is an efficient payment mechanism because it is p2p and there are no natural monopolies so (economic theory tells us) the cost of transactions will be low. Low doesn't mean zero.