Geodicity is an app for creating publicly viewable, geolocated messages that generate notifications. In the Geodicity community, everyone is anonymous, and everyone is an admin. So vote for whats useful, and delete what isnt!
Geodicity is great for generating a wiki of the here-and-now. Tell nearby people about awesome festival booths, free giveaways, or transportation issues. Make a note for whatever is useful and cool nearby, and notify your world!
Standard App Store Battery Disclaimer:
Continued use of GPS running in the background can dramatically decrease battery life.