Socialight is a location-based information service. Geeks call it "geo-tagging". With this service, you can create Stickies anywhere in the world for your friends, for everyone, or just for yourself. They can now contain text and photos, and soon you'll be able to add sound clips and video.
Watch this video to learn more:
The company claims benefits like:
There are obvious concerns and critics with anything new, especially as it relates to security. Not that I believe anyone will be stalking me, there are some who this may be an issue.