I think one can make the distinction between i) a website that has some independent ads targeted on your profile on this very website (this is ok for me) with ii) a network like Google Adsense which can follow you among various websites (kind of scary for me as well).

Yeah this is quite an interesting point. On one side, no one can escape commercials, so I want at least see commercials which are interesting for me. On the other side it can get kind of scary: You visit a cd shop for a special band you are interested in, but then leave the site without buying the cart … while a browsing a news site, thanks to the wide network, there is a add which says: “hello. Still interested in …. scary, I think