Exactly that. It's a deep-in-the-datastream traffic analysis that pipes targeted adverts to you. It is allegedly anonymised, but I never believe that.

Basically I don't want ads for goatfelch.com (derived from my foul evening surfing) appearing during the day while showing some cool Wiki article to somebody. It's none of their business and I don't want the adverts at all, never mind 'targeted' ones. And that's assuming that we trust them not to do all sorts of intrusive other screening. They can, simply, feck off.