Have you used infolinks for monetizing your website? I think it can work well on forums, I have seen some forums using infolinks only, don't know how much they are making from it, but I have checked their revenue offers, they are alright for an in-text ad service. And I also want to ask that does it bother you if a forum or website has in-text ads on? I mean it does bother me. They are not that user friendly to me at least.