Site Name: Physics Forums
URL:
http://www.physicsforums.com
Description: Science and Homework Help Community
Reason for Nomination: Could very well be the highest quality of discussion anywhere on the web. Virtually zero spam. 20+ Staff that is grad student level and above. Nearly 20,000 homework help questions worked though. Custom LATEX addon. It speaks for itself, again extremely high quality of discussion as we have a zero tolerance crackpot policy.