We have covered the fun and the dark side of location software on this blog before.
Examples of Check In Software: Facebook Places, GoWalla, Foursquare, Loopt - once you check in, I can find you on a map.
Examples of Location Aware Software: Twitter allows you to turn on your location when you tweet
Locate your friends & family easily
Earn rewards points
Reputation: You may be broadcasting an image, based on where you check in, that you don't want to broadcast
Stalking: Young people or women traveling alone open themselves up to potential issues
The US Air Force put out a warning recently to its troops to be careful when they use social media networks because many of the new features show exactly where you are when you use them. This is potentially devastating for U.S. forces in war zones.
To put it into perspective, we have roughly 95,000 troops in Afghanistan and approximately 50,000 in Iraq.
If you have loved ones serving overseas, thank them for their service and then show them this warning and ask them to be safe.
Sources: "Air Force Warns Troops: Don't 'Check In' to Wars", Associated Press, November 18, 2010.