Hehe, but if you never post on some of the free boards, you may never make their webmasters addicted to vBulletin. I have a few webmaster friends who uses boards like phpBB and Invision Board. I post frequently enough to get people to visit my forums, and they always seem to be commenting about vBulletin and how fast, customizeable and beautiful it is.
In short, webmasters get jealous and now wants their own copy of vBulletin