It's extremely hard to find a gap in the market, when there are billions working on it for a living.
I think it'd be quite cool to have an anomynous (if you choose) forum/chat for teens to discuss teen things, in quite a lot of detail. Problems, relationships, parents, sex, entertainment etc.
That or underground underage porn network. I'd really love to find an underground site where underage teens webcam with eachother... 8-)
