But no one has yet made the corollary observation that web sites are doing this in lieu of spending on their own medium. Web advertising doesn't really work. Yes, but that's not to say that just any page can get by on banner ads. We can do it here at I, Cringely because, well, I just work too cheaply. Most commercial web sites have a much harder time than I do.
Most sites have a hard time selling ads at all.
It's a sordid little bit of truth that most Web ads aren't bought for money. They count on barter deals in which one overpriced Internet company gives free ads to another overpriced Internet company. These banners were in very popular sites like AOL, Microsoft, Lycos, etc. We just traded for whatever else we could come up with. And I've got to think that other people are doing the same.