Kaioo.com

Kaioo.com is a social networking site that donates all advertising revenues to charity.

"Every user can nominate a charitable project to receive donations from kaioo at year-end. The user can create a discussion group for the project in the "charity voting" category and then try to attract members. At the end of the year, the 10 projects that have received the most votes will receive a donation from kaioo proportionate to their share of the vote." (quote from kaioo.com)