Oh, and on topic
Yes, I have bought over 20 sites and sold about 30. I think all of them were on Sitepoint.
Also, some of the biggest sites I own were as a direct result of me watching the marketplace, seeing what sold for a large sum of money and creating something similar.
Sitepoint Marketplace is a GOLDMINE of money making ideas.
No nasty surprises either. In fact, the only way I got into the top
CPM advertising networks was by buying a site that was already approved.