I'm a blogger, so I guess by default there's an aspect of my life (my work life, at least) which is super-public, like what you're reading right now. But there's a line I draw in the sand when it comes to sharing personal stuff on Facebook and Twitter (and I have not even bothered exploring the possibilities of Foursquare, et al). We've all rolled our eyes at friends who insist on sharing banalities like what they're having for lunch (don't you people want any part of your lives to remain a mystery?), but there's yet another, increasingly-recognized downside to over-sharing, which is that it can make you rob-able, stalk-able, and sometimes even fire-able.

That first link heads to Please Rob Me, a now-offline site that was a stream from various location-based services that show the the whole world when users aren't home. Here's their mission statement:

The danger is publicly telling people where you are. This is because it leaves one place you’re definitely not… home. So here we are; on one end we’re leaving lights on when we’re going on a holiday, and on the other we’re telling everybody on the internet we’re not home. It gets even worse if you have “friends” who want to colonize your house. That means they have to enter your address, to tell everyone where they are. Your address.. on the internet.. Now you know what to do when people reach for their phone as soon as they enter your home. That’s right, slap them across the face.

I Can Stalk You, on the other hand, illustrates the dangers of oversharing via geotagged photos, which people love to link to on Twitter and upload to Facebook. After analyzing your photos, I Can Stalk You says, someone could find out:

* Where you live
* Who else lives there
* Your commuting patterns
* Where you go for lunch each day
* Who you go to lunch with
* Why you and your attractive co-worker really like to visit a certain nice restaurant on a regular basis

As for the third link, I think we've all heard the stories of people who've been fired because of Tweets or Facebook updates. It's an old but depressingly common story.

What I want to know is this: do you have any rules about what you will or won't share online?