I use Foursquare to share location data. I use Blippy to share purchase history, and I even use OneTrueFan to make my Web visits public. This hasn't been done with a reckless approach to privacy where I have thrown caution to the wind, but instead, has been more calculated. I believe the major trends on the Web encourage sharing, and if I can be the one sharing and not reacting, I am ahead of the game.
See CNN: The Internet and the 'End of Privacy' for their insight into my sharing behavior.
Some would look at what I choose to share and could suggest I feel that privacy is "dead". I don't believe this at all. What I do believe, however, is that intelligent sharing and knowledge of where personal data is distributed can bring value. Rather than take a more conservative approach, locking down what in other generations would be secret, I've opted to own what is shared, and to operate my life as if what I was not sharing explicitly would not be a disaster if it eventually were to be surfaced.
One needs to look no further than Facebook, the world's dominant social network, to see how the company's approach to privacy has changed in the last few years. Once a stalwart site prized for how it protected your content from prying eyes, more content has become public in practically each update. While some have suggested the best solution is to lock down one's profile, I have instead assumed the content will eventually become public and discoverable, shared to advertisers. This was one reason I downloaded an archive and self-hosted it, making the full copy available myself. (See: http://www.louisgray.com/facebook/)
But even with my level of publicness comes limits. I don't think it makes sense to chronicle the minutiae of my day through status updates. I don't muddy my main broadcast channels with location details, shopping updates or entertainment. I don't air embarrassing scenes with my wife or my kids. I don't post content of them that would be unflattering. And I try not to bore people with inane blather.
For me, the major reason I don't share some things is not because I am frightened my content will be used against me. After all, it took a simple e-mail account hack to get me fighting back on that front earlier this summer, and it wasn't tracked to my use of any of these sites. The major reason I don't overshare is because I believe it wouldn't add value and it would be boring to all who saw it.
In a conversation I recently had with a reporter from CNN.com, he asked if there were parts of my life I would be reticent to share if my transparency were further peeled back. The answer was essentially no. The trick is to live your life in a way that if your employer or future spouse were checking in on you, you would have nothing to fear. This doesn't mean you can't have a good time, but you should assume a consequence if your actions were to become public. Manage yourself well and what's discovered shouldn't turn an eye.
We live in a world with many imperfect people, and some really bad ones. That's no question. But I don't think being afraid to share and reducing the amount of personally identifiable information is the right approach. It makes more sense to assume the world is full of great people, cultivate the ones where this is known, and to be smart about what you share, and where you do. Watch the big networks to see if you think they are taking liberties with your data and prepare for the eventuality if they do.