The idea and scope of ads has purpose there is no question. Granted the revenue they generate is often trivial at best.
The side effect in some situations is the ultimate negative. When people visit from networks run trough a content filtering/restricting mechanism what happens in some cases is COMPLETELY ELIMINATING their ability to visit at all because this mechanism can blacklist the entire domain!
I deal with the above daily, right now my ability to visit hasn't been restricted yet, but it will be! There are many places on the internet restricted because their hosting service hosts something else considered *bad* so the entire IP address range is locked out. I haven't been able to get to roadracingworld.com for a long time because of this. Anything the average joe can get to, I can't during the day.
So, like I said, for lack of any better qualifier, banner ads suck!
Is there any intension of a pay for membership (oh that's right I already do that) to not have them?