The heart of the co-ed is fickle but coveted. While Yahoo fusses with social networking "experts," Microsoft decides to hunt down some brand ambassadors, according to a press release by the firm chosen for the task: RepNation Media.

RepNation Media has chosen 70 brand embassadors across 35 college campuses to host events, infiltrate local causes and build press. They will also be building name recognition via WOM, blogs and social networks.

The brand-building efforts are intended to promote Microsoft's i'm Initiative, which enables people to raise money for worthwhile causes while chatting via personal messenger.

Each time a person begins an online conversation via i'm on Windows Live Messenger, Microsoft will donate a portion of the ad revenue to one of nine major cause-oriented organizations. The user may select which one.