[petertodd]

Huh? $280/tx?

Maybe some people paid fees that high by mistake, but no-one had too. Equally $20/tx fees are still ludicrously high by about three orders of magnitude.

Bitcoin miners prioritize transactions from highest fee to lowest; the attackers never sent transactions with more than 0.2mBTC/KB fees, which works out to about $0.01/tx. In other words, if you paid more than about $0.01 in fees, your transaction was unaffected by the flood.

The problem was a lot of badly written Bitcoin wallets don't let their users set fees at all, nor do they let you resend transactions stuck due to low fees. This is an easily solved problem, and fortunately we're seeing wallet authors fixing it. This should have happened years ago... but a lot of people are heavily invested into the idea that Bitcoin transactions are "free", which just isn't true...

You may find my writeup on the flood useful reading: https://gist.github.com/petertodd/8e87c782bdf342ef18fb