Timelope (http://timelope.com/) is a similar project started by Aviel (http://timelope.com/index.php?p=user&username=aviel) through Six Hour Startup here in Seattle a couple months ago. It's a Firefox browser plugin and keeps track of every site you go to (by default, the info isn't shared). From what I understand, it's got some brains on the backend to cut down on showing duplicates of the sites you visit.

The question is, do you really want people seeing a list of every site you go to on the web? ;)