Loopt Snags AT&T, Now Available On Every U.S. Carrier

Mobile social network Loopt goes live on three AT&T phones today, which was the last major carrier holdout. Loopt is now available in the U.S. on Sprint, Verizon, Metro PCS, T-Mobile and Boost. The service is free for a year and then a $4/month fee kicks in.

You can get Loopt for free on the iPhone (and there is a TechCrunch version), the Blackberry and Android as well.

We’re big believers that mobile is the future of social networking. Loopt and a handful of other brave startups are pushing the envelope on mobile social networks while the big guys, Facebook and MySpace, sit on the sidelines.

A big reason they’re hesitant – privacy concerns. Both companies have had their run ins with the press and state attorneys general. Mobile social network is all about location, and finding people around you. That’s not where Facebook and MySpace want to go right now.

That leaves room for Loopt and others to grab market share. These services allow users to update their location and share it with others. People who are on the network can contact you, if you choose, just because of where you are even if they don’t know you.

One feature that hasn’t hit the iPhone yet is auto-updating of location. But it appears to be on AT&T’s general rollout on other phones. I’d expect to see it released soon on the iPhone as well. That means that, theoretically, your friends can find out where you are (if the feature is turned on) on demand. yes, there are big privacy issues there, but it’s also the future.

Disclosure: Loopt is in the middle of a patent litigation suit, and the plaintiff in that case dragged us into the middle of the fight.