in a threaqd somewhere someone asked this befor. they talked about a free web host that supports vbulletin. like sign up for a free site and add vbulletin to it
Because from experience, most vB running on free hosts are pirated - the feeling is that people who can afford vB can afford to host it. Mind you, this is obviously a generalization, and is not always the case.
My guess would be that most folks interested in free hosting, may not have taken that all important step of actually *purchasing* a license for vB. Or it could be some completely unrelated random reason, like an admin with an unexplained childhood hatred of words that rhyme with whee!