Some people are going to be weirded out by this "retargeting" thing. I don't think it quite meets the level of something that privacy advocates can complain about, though. It's just an agreement from ad networks that they'll show your ads when they see your cookies in a request. Ad networks function by reading cookies, so if you accept their existence you accept the basic practice. This is just an interesting new wrinkle.

I'm waiting for the first stories about people having their Christmas present surprises spoiled by their SOs seeing retargeted Amazon ads featuring the products they were browsing while doing their Christmas shopping. Or their kids seeing retargeted Toys R Us ads with the toys the parents were looking at. :)

(I don't think retargeting is bad in general, I just think that the shops that due the specific-product-including ones are treading the wrong side of the creepy line and haven't thought enough about shared computers.)