I think you are mixing up the fact that IT has a large userbase, while ML, NLP, etc; are more niche (relatively speaking). 360 users IS immediate traction for this area.

> Clearly, it takes more than 360 people to make a site successful.

Successful for it's founders, yes. But for me, the reader, I'm quite happy to have only the few thousand most-active researchers and professors and their students of Machine Learning, NLP, etc; post on metaoptimize.com. Otherwise, I might as well go to Yahoo Answers for generic, watered-down responses.