Another spot where the analogy breaks down is that I don't think of a non-ecommerce website as a kind of store. I think of it as being more equivalent to a magazine or newspaper. And in those cases advertising is certainly present, but the overall experience is much less overtly invasive to me, the consumer.

I also suspect that non-ecommerce website publishers really would rather think about their websites as being akin to magazines. They aren't really in control of what gets put on their page through the ad networks in the same way that print publishers are, and I can't imagine many editors are terribly thrilled about the things that ad networks place alongside the content they produce. I really kind off feel bad for them; they're caught up in a pretty terrible Faustian bargain.