It's not excessive it's what they do, they're a terrible breed of website. You don't just make money from people clicking your ads simply them being viewed is enough.
I know that they make money from viewed ads. What I'm saying is that such ads won't actually affect anything, assuming the viewer base is intelligent enough to know bullstuff when they see it.
Sure they're making money off it, but hey, it's the advertisers who are throwing their dollars away on the site. The real problems start when pampered rich bums see something that they "absolutely MUST have!" or "MOMMY I WANT I WANT I WANT WAAAAAAAHHHHHHHH" and someone actually BUYS it.
True that advertising leads to publicity, but you are going to run into that everywhere. Deviantart does it and is somewhat infamous for poor handling of art theft reports (which is actually just due to a small and overloaded support staff and constant duplicate reports by a bajillion different people).
The Blockland Forums (and now to some limited extent the RTB forums due to lubhosting) are the only sites I can think of that involve for-profit deals but do not throw up way too many awful advertisements, and that is all because Badspot is a sensible guy who understands just how annoying advertisements are and takes a moral and ethical standpoint on his forums.
