Windows Live Messenger

Windows Live Messenger includes support for the im Initiative! Every time you start a conversation using im, Microsoft shares a portion of the program's advertising revenue with some of the world's most effective organizations dedicated to social causes.

Windows Live Messenger Website

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So any time you have an im conversation using Windows Live Messenger, you help address the issues you feel most passionate about. It's simple. All you have to do is join and start an instant messaging conversation.