Global Philanthropy Forum [ http://www.philanthropyforum.org/ ]
Aims to build a community of donors and social investors committed to international causes, and to inform, enable and enhance the strategic nature of their giving and social investing.

Vote.com [ http://www.vote.com/ ]
Gives you a voice on important issues. When you vote on a topic, an e-mail is sent to decision makers like your congressman, telling them how you feel.