A fair number of people have been shocked and outraged that information they post on Facebook and MySpace has come back to haunt them. I don't know why though.

I've always shied away from these social sites for exactly this reason -- the more people know about me the more likely I am to get in trouble.

I don't understand the shock or the outrage. For that matter, I don't understand why students chose to plead guilty to a crime when the only evidence the State College Police Department was holding were posts on an Internet message board. That's a column for another time -- back to the shock and outrage.

People go into these social sites and post personal information, their class schedules alongside pictures of themselves in all states of undress and inebriation. How did they not see this coming?

Perhaps I can't empathize because I've spent a lot of time on the other side. I was a Resident Assistant (RA) for two years and I can tell you diehard RAs used Facebook to track down vandals, drinkers and other general misanthropes. This kind of stalking isn't just local; I've seen it from coast to coast.

I used to work for a small tech company and one of my duties was to build e-mail lists of executives who could use our products. I was given a name, a company and an Internet connection. That's all it took to track down e-mail addresses, and if I had so desired all manners of personal information, including appearances in newspapers, family photos or forums they posted on.

The underlying problem is that people have a hard time grasping that the Internet is actually just another community. The Internet doesn't grant you the anonymity of the ski mask, it grants the anonymity of the large crowd.

When you surf the Web, you leave a trail behind you that can be tracked.

When you access a Web site, your IP address is noted by that Web site. The operators now have a number that tells them when and how often you have accessed that site. Now your IP address can't be linked to you unless your Web provider allows it and so far their track record has been pretty good for defending the privacy of their users. However the government has been pushing for more surveillance and public outcry against it has been unremarkable. I question how long it will be before the government gains access to a full database of when and where everyone goes on the Internet.

The point is that truly interested parties are using your information all the time. Give a guy your number and there is a fair-to-middling chance that he's going to research you on Facebook to make sure you aren't a turfgrass management major or something equally embarrassing. It's not just your social life that's on the line.

Information you post on Web sites is fair game for employers and law and enforcement. When you put compromising information up on the Internet you compromise your chances at employment and expose yourself to legal prosecution.

You have to be proactive in defending your personal information. Failure to do so results in exposure to all kinds of problems. Facebook is a great networking tool but it is also a stalker's delight. Bear in mind that your privacy is defended by companies that will do so only as long as it's in their best interest.

Every time you give President Bush a pass on eavesdropping you send him the message that you are willing to have your privacy compromised. They are capitalists if they think it won't cost them customers you'd better believe they would turn your information over in a heartbeat.

And if you are using a wireless network in your apartment make sure you put a password on it. It's possible for the less scrupulous person to root around in your iTunes library and discover your Lynyrd Skynyrd fetish. Seriously, four versions of "Freebird"?