Nice headline, but not really an accurate portrayal of what really happened. Definitely a "marketing" story more that sounds a lot nicer to tell and hear than the nitty gritty that actually went on. If you look at the stats of the forum they get very little traffic (relatively), and the forum itself is pretty barren.

Therefore, I highly highly doubt that the majority of the revenue is coming from the community itself. Rather, it sounds like the forum is a legitimizing component that is essentially a front for the money making schemes behind the back.

This happens a lot with affiliate and domain sites.

You have some lucrative affiliate relationships that you can hardcore SEM against, however you need a site that looks good if the advertisers ever check you out. So what they do is usually purchase a respectable site, has the air of a community, looks good, etc. And then they have this shadow site that runs off the same domain that they arbitrage against with pages that are super ad/affiliate heavy and make tons of money.

Combining a legit domain/site with an SEM shadow site is also useful for making sure your AdWord rates stay lower. If your domain has more authority and natural SEO traffic/PR then it seems like Google won't charge you as much to get higher SEM listings.

It's actually a "simple" model and can be EXTREMELY lucrative. However, it doesn't really add much value to the world, and they can go out of business in an instant if the CPC rates change in any direction.