If you want control, you have to pay for it. It is all very well getting free hosting but what about if you want a backup, ah, you have to wait, what about if you want to install a nice little blog for your websites, ah you have to wait. And what about when your host decides your too big for their services, with a paid hosting account you dont get all of this you get control, great service and the flexibility to turn your forums, and/or websites into something impressive.
Most big forums are spending around $500 a month on a reliable dedicated server