This is a bit controvesial topic - but I believe eventually there will be a discussion about it here, so I provide the link to their site: www.affero.com and the interview posted recently on slashdot. In short it is an reputation system for online identities.

It seems a bit naive at the first look, especially when you look on the graphics on their website, but what is strong in it is the idea to transcend the site boundaries, and have your reputation go with you from one community to an other.