People make a forum account and do nothing wth it.this percent of the population outwieghs even those with a meager 10 posts.So I wonder why make an account when you might as well be a guest all the time.It just doesn't make sense that so many people would do this.

Probably failed advertisers and lurkers. People used to make accounts and change the birthdays to the next day each time so that they could advertise a site when someone clicked on it.