Oh dear, every now and then you come across something new and you just know you’re going to be spending a lot of time on it. Stackoverflow.com is a great merit-based questions/answers community for developers. I’ve only just got started there so my reputation score is low, I’ll link to it once it’s looking like anything substantial :). Looking at the score of some other guys, it seems to me like they must be spending hours a day on it.
The benefit for those guys? When looking for a job/assignment, they can simply point at their Stack Overflow profile and every employer will understand that they’re dealing with somebody very competent.
Apparently, the people behind Stack Overflow are looking for investors. If I had a big bank account I would consider it