Like Kylearan, I use the Opera browser, so I have no idea how bad any problems are here. Completely immune to popups, spyware, and any other ActiveX crap. I don't even get Flash when I don't want it. Anyone who does as much browsing as Sirian does should definitely check it out.
I don't think another free service is really an option. EZBoard flings around all sorts of ads too, and I'm sure just about any free service would do likewise.
RB as a whole is kind of in-between as far as size. Too big to really fit in with free services like N54, too big for Sirian to host at warpcore or me at my own server, but really not big enough to justify its own server on the scale of the Lurker Lounge or Amazon Basin or CivFanatics.
I would like to see RB on its own host with minimal ads, of course, but like most everyone here, I'm not up to taking the lead in such a project myself. I could help with something like porting over old posts from N54, and I'd certainly help financially.