Federated Social Web stuff.
It seems privacy can't really be pinned down, the definition is evolving. But you can effectively use a working definition (pick one).
Things are different depending where in the world you live.
Your average internet user hasn't a clue.
What's being leeched from your online activity - virtually nobody takes on the implications. But people are learning, they're as far as 1999.
Even when the browser vendors get together and make a button to limit things - still no-one gets the implications (see Aleecia at the link above).
Ok, so far is mostly "duh!".
But there was a lovely little revelation (from Soren I believe) that statistically the people more aware of privacy tend to be those with more disposable income [bum, that's twitterable]. If you want this demographic's dollars in your consumer base, you better get your privacy sussed.