[sp332]

There is some monetary value, in transaction fees, that are collected even if there is no block reward. There will be fewer people, but hopefully it will still be above critical mass. It really doesn't take much, even a few hundred people running low-power ASICs will do just fine. We will see something similar with Doge soon. In 2015, the payout will be fixed at 5% of what it was last month. Maybe everyone will stop mining, and maybe they won't.

[ars]

> It really doesn't take much, even a few hundred people running low-power ASICs will do just fine.

That won't work - it will enable easy fraud since anyone with a moderate amount of computing power can fake the block chain.

You need a lot of computing power - but without large rewards people won't be willing to do it.

I don't expect any crypto currency to survive unchanged past the no-more-coins date. Instead I expect the date to be extended to forever.

[maxerickson]

There's a good possibility that is still pretty optimistic.