The main idea is to log a user's activities on the system and then ask questions about them when they login next time
it'll be interesting when the system asks "what was that porn site you visited a lot last time?"
what google does is not fair game
What google does is not ethical game. Deontology in nowadays big companies is long gone. Basically, the big groups as of today are money machines - their performance assessment is basically the result of the equation Revenue - Charges. Fairness is not involved, Compliance with the law is, because lawsuits are the only thing companies are afraid of, nowadays, i.e. losing a lawsuit = inflate the "Charges" account. Google does what the law allows them to do - they own a large team full of people looking for ways to save money, legally.
I find you lack of faith in the forth dithturbing. - Darse ("Darth") Vader