[DennisP]

https://blog.ethereum.org/2015/08/01/introducing-casper-frie...

[anarcat]

TL;DR. What's the takeaway?

[jbpetersen]

Instead of a hashing contest it uses time locked deposits on which block will be accepted next.

To my understanding it works out as a combination of prediction market style betting and bidding for a block to be accepted.