I gotta admit that's one that surprises me.
For the most part, I have no problem with the theory of "targeted advertising." The problem I have is that with all this data that is supposedly being soaked up, it does a pretty crappy job of delivering ads for things I might actually be interested in. Yeah, I suppose it does a good job of filtering ads that I absolutely have no interest in--I haven't seen a "Pampers" ad or something like that.
I'm somewhat in the market for a new car. I like small convertibles/roadsters. I went and checked out the Mini Cooper Roadster on Mini's website and then checked a bunch of the dealer websites to see if they had the options that I wanted in stock (none did). And for the next few weeks, I was seeing ads for the Mini Cooper Roadster from various local dealers whose websites I've already visited!
Yes, I've been there and seen it. I would think it would be showing me ads for the Mazda Miata or Audi TT--similar roadster-type cars. I would think it would showing me ads for dealers a bit further afield.