A fascinating product was pitched by Don McLagan here at PC Forum: Upromise, a downloadable toolbar that watches your surfing behavior and pays into a 529 (college savings plan) when you buy stuff (it's like Amazon A9, but pays you differently). The company makes money by selling your click-stream data to the merchants you're buying from. About 3 to 5 percent of your purchase is put into the 529, and Compete, the company that runs Upromise, makes even more than that from collecting and reselling your data. Which indicates to consumers what their behavior is worth: something more than 5 percent of their purchase.
Upromise thus puts users in charge, sort of, by making it clear to them that their personal data is worth something. It doesn't give them complete control, just a glimpse into the financials of their click-stream data and a bit of a bribe for giving it up.