Loopt and Whrrl are trying to break the door down on a potentially huge new market by convincing phone users that it's totally cool for your friends to know exactly where you are at any given time. Potentially scary, yes, but the benefits are obvious -- and when all the security and privacy issues have been squared away, it could be a big deal. Nokia's diving into the fray now with Chat, an IM client currently in beta that integrates with your contact list and allows selected friends to see one anothers' locations in real time. That in itself isn't novel, but the app also allows you to mark off landmarks which will automatically trigger broadcast messages to your friends with zero involvement or interaction with the phone. Kinda nifty for letting folks know when you show up to work or school, for example -- as long as you're not chronically late, anyhow. Follow the break for a video intro of the system.