Some people have the idea that they can use Forums as a cheap way of Advertising. Some Forums allow people to post their own site information within any thread and at most Forums, within specific areas. So to get around restrictions and post in as many Forums / threads as possible, they sign up and make a post, in the form of a question with their site being mentioned of course. Or they'll have others signup at a Forum to make specific posts about the good service/hosting they've gotten at so-and-so.
It is a dead giveaway when the Post count is very small and the post(s) are in praise of some Hosting company. Or, as mentioned, in the form of a question -- because said company looks sooo good.
This is all just another form of Spam and just like we don't appreciate it in our eMail, most of us don't appreciate having to wade through it within Forums. If they want to advertise, then pay for it like the rest of us do.