Web of Trust (for bitcoin-otc)

For the official explanation: http://wiki.bitcoin-otc.com/wiki/OTC_Rating_System

A nice 'high-level' overview by everyone's favorite guy, Mircea Popescu (opinions aside, the guy makes a lot of sense about a lot of things Bitcoin): http://trilema.com/2014/what-the-wot-is-for-how-it-works-and-how-to-use-it/