Any magazine company that pays $100,000 for web forums that get a few hundred hits a day will be in very bad financial status quite soon.
Im not professional in this, however i will take the average revenue of the past few year then multiple 2year. Don't ask me why 2yr, i just tink any higher value, the buyer will turn down the offer.
How did you even come up with the $100,000 evaluation? No one in their right mind will pay that much for a forum that only gets 200 visits a day.