Social Software: Privacy and Misuse

So Facebook, Twitter and YouTube are hip and cool, I know.  Add to those, Amazon and eBay.  But what about all the private materials you post and all those recommendations and reviews you post?  You think it's totally private and without a "cost"?

What about the state looking to see if you are paying your sales tax on those books and DVDs?  A New York Times article says Amazon has the data and the state may get a search warrant for it.  

What about the data-mining Facebook does and shares with its advertising vendors?

Or what about the fears of overshare?

For those of us who came of age, technologically speaking, in the Web 2.0 Era, it may be too late to cancel, delete or otherwise redact what’s out there. Basically we have to deal with cards we’ve dealt ourselves. One could argue that if you choose to live your life in public you don’t get to control what other people do with this public information. You can, however, choose how much of it to put out there.

And add to all this the possibility that HTML 5 may implement more aggressive data-mining practices embedded into the internet.