Amy Sample Ward has done us bridge builders a great service. She has created a collection of case studies around the topic of Social Media for Social Good, which is, essentially, organizations that get behind a social cause writing about their goals, approach, etc.
But aside from gathering what people are doing in the name of social good, I think these studies provide readers with excellent examples on how to go about making creative bridges to our communities. She, along with Beth Kanter, presented the winners at the NTEN (The Nonprofit Technology Network) this past March. but you can check out the full range of submissions here. A wonderful idea bank for social media connection!