At UC Santa Cruz there is a Livejournal community with an end-of-quarter "post anonymous secrets" thread. Exactly what is described here, and very popular. I think other campus LJ communities did the same as well.

I'm surprised at the critical attitudes -- that there are two competitors is reason for encouragement and indicates that the market you're targeting is no illusion. All you have to do is make your site better and better-known than the other guys.