[rmason]

Here's one he forgot: I've seen niche content sites that after building a community hold conferences. They may have advertising but it's the conference that's their main money maker.

[balajiviswanath]

That's a good feedback, rmason. It is a niche model that could be added to the article.

[justincormack]

Its not that niche eg TED.

[camus]

quite a lot of enterprise opensource software companies do that. And their gigs are not cheap ;)