I think part of it comes down to so many animated banners just being so... cliche, cookie cutter, identical to one another. Just like so many of those 3-page tour sites are. Same loud, clashy banner, same WMP frame graphic, same little camcorder graphic with different image inserted in viewfinder... same same same. Even the same lil catchphrases, almost regardless of the kind of site they're promoting. Surfers will zone that stuff out lickity split.