Loopt is a new social networking app for Windows Mobile/Phone users: think mobile Facebook plus Twitter plus Google Latitude a dash of FourSquare with a bit of Yelp!
Yeah, pretty crazy. Not sure if it will catch on, but evidently they can tie it all in with Facebook, making it quite easy and painless. Unfortunately for now, you'll have to sign up for a Loopt account for WP7, until they add that feature later. Not sure if the world needs another social network, but then again, this looks like "one to rule them all" plus it's already available on Android, iPhone and Facebook, meaning we won't be alone out there.
Source: Robert Scoble