Pretty much what the title says.
What happens when all 21 million (I think that was the max number) BTC have been mined? How will transactions get verified?
Just generally, what happens?
Also, if verification gets slower than transaction amounts (because of the difficulty, and by amounts I mean how many transactions there are; more people using BTC, more transactions), what will happen to the transactions? Will they get delayed for days?
People will still mine for the transaction fees, just less... and the difficulty would adjust accordingly..