The Confessionals (starting from the Oberlin Confessional) is a set of open message boards that are strictly accessible only in their respective communities. Due to the open yet closed nature of these Confessionals, they are an excellent means of quick, frivolous and community filtered discussions within a community. (see http://www.oberlinconfessional.com/)
The idea began with a simple LiveJournal thread started by Oberlin Alum Anna Leuchtenberger and was a major hit on the Oberlin campus. Afterwards, the idea was converted to a simple database driven website by Harris Lapiroff but was closed down quickly due to various abuse issues. In 2006, my friend and associate Shibo Xu bought the domain name and all related assets and asked me to come aboard as a programmer and system engineer. I re-developed the website using the CakePHP framework and hosted the website on our own servers. Soon, the concept was extended to other colleges in the same league as Oberlin, and found a similar fan following everywhere. Better filtering features have been added to the websites over time, and we're working on more ways to use human as well as machine decisions to maintain the forums open while completely eradicating abuse.
We haven't been without critics, though, and so, we continually make efforts to improve the website for everyone.
Note: I'm not involved with the Oberlin Confessional anymore
Here are some related links: