I'm genuinely curious -- I've never been particularly concerned about privacy on the internet, and it seems like the author's main concern is better ad targeting (which I see as beneficial, although I may be in a minority). What are some other dangerous scenarios that people can imagine?
In order to create this 'targeted advertising,' they create huge databases of information on people. People called this creepy when the FBI was doing it, but it's ok when a private corporation does it? It's not like the FBI/CIA/MI6/etc doesn't just send a request to the company and get your data anyways... So I'm not really seeing the difference between any company having access to this information and the government…
It's covered here http://www.privacyrights.org/ar/ftc-info_mktpl.htm (buried deep in the page)