Slightly intrusive but the ads do pay towards keeping Pprune going so it's no real cause for complaint in my opinion.
So it does, However, The advertisers and Forum owners (not just this one) don't seem to get the idea that people hate obtrusive advertising. Hence the invention of and universal use of Adblockers.
It seems pointless designing a well laid out forum and then sticking something like that awful google side Ad into the equation.