Well, Netflix thinks they're for helping you find the movies you like. Netflix has built in a feature that lets you comment on and rate movies and share your opinions with a group of friends. In return, you can see what your buddies had to say about something you were thinking about renting. This is, with a few bells and whistles, the old fashioned way of learning about a movie. Friends are how we learn about books, clothes, art, restaurants, cars, dates, and causes (among other things). We trust the opinions of those we know. We join boards when asked by friends (or colleagues), we give money when asked by friends, we attend rallies when our friends are going, we turn to our friends to support the things we care about.
So why don't more foundations use their friends? Why don't foundations that care about certain issues try to get their friends to care also? Why is endorsing an issue, an organization, a strategy, or a cause the purview of individuals and DVD rental companies, but not the norm for philanthropic organizations?