More details on Google Sites
In October 2006, Google acquired JotSpot, a hosted wiki platform for building collaborative Web sites. Sixteen months later, which is like 10 years in Web time, Google is launching a revamped JotSpot as Google Sites.
Rafe Needleman at CNET Webware has a more in-depth post on how Google Sites works.
The term "wiki" has been banished from Googlespeak as the company tries to mainstream its collaborative applications. "There shouldn't be a distinction between wikis and sites," said product manager Scott Johnston. He hopes that the "edit button" becomes pervasive as the collaborative Web takes hold.