During Chi, I had a few gatherings with my old school friends from Media Lab Europe. This reminded me how fun it was to be beta tester for each other's project. Back in Dublin, I tried out Jonah and Mike's Bumplist.
BumpList only allows for a minimum amount of subscribers so that when a new person subscribes, the first person to subscribe is "bumped", or unsubscribed from the list.
Via Jonah again, I tested the super fun myfrienenemies social community. Basically, on this site, anyone can post anonymously about their enemies and connect to others through their enemies.