I will join several facebook math groups for the sole purpose of advertising Jason's site.
Years ago I made an account at Yahoo Answers and my answers consisted of the actual answer, and then a link to a thread at MHB to see the actual work done using LaTeX. I figured that would be okay, and I answered hundreds of questions that way until one day one particular person began reporting all my answers, and I eventually got banned for spamming. I won a few appeals, but this same person kept reporting all my answers, and eventually the ban stuck.
Funny thing is, most of the answers at Yahoo stayed open, and I still see a lot of traffic at MHB from those answers. People have to register to see images, and other features, and we get a lot of people registering, but very few actually post. They register so they can see everything, consume what they came for, and then never return. So, it works to drive up membership numbers, but does very little to increase actual participation. People suck, in general. That's my takeaway from the experience.
Yeah, it seems like a few regulars are the ones giving the most activity. Anyway, though, if it's a business operation, then a lot of traffic, even if it's just regulars actually posting - could still make a lot of money (clicking on ads).