We are not alone with our Geo Messages
"Services like Loopt and Google Latitude can broadcast a user’s location constantly, but that can eat into battery life and can also prompt privacy concerns. By pulling location rather than pushing it out, Echoecho lets people control when and how they make that information available to others. And since it can be used without both parties owning the app or joining a social network, it’s a simple way to provide location updates." - well said!
Glad to see Google Ventures agreed with our opinion about peer to peer location sharing.
You can see also the presentation from ICUMT-2010: