A number of ski resorts this season have combined mountain fun with location based social networking in a new service called Epic Mix. Rolled out to 5 mountains this season with more to come next year, the service logs your vertical feet and awards you pins based on mountain exploration.

Mike Slone, Interactive director, Vail Resorts: "It all starts with an RF chip that's embedded in our passes in our Peaks lift cards. So what that means is there's an RF chip embedded in the pass and as users ski through the mountain, they go through what we call gantries. Gantries are these metal structures of sorts that people don't typically notice. But as they ride a lift they go through these gantires, we scan them so we know where they're at on the mountain. From there the gantries then connect to a database and a web app that allows us to calculate vertical feet and then we award digital ski pins for exploration on the mountain and as people get various vertical feet."

The digital ski pins are of course a reference to physical pins that skiers collect from different mountains. With après ski tales being all about bragging about double black diamond trails and knee deep powder, skiers and boarders can pull up their latest conquests on an iOS or Android device app or through the web. Epic Mix is similar to location based social networking app FourSquare, but one way it differs is that you don't need to check in manually.

Slone: "It allows them to go about their natural ski day. They're doing what they've been doing all along and it doesn't require any special technology other than your pass. It doesn't require that you have a mobile phone or that you get your mobile phone out or have a gps device. You go about your day as you've always done, you ski, you have fun and then if you chose to you can log into your Epic Mix account. You can check it on your iPhone or Droid app and then you can choose to look at your vertical feet."

Slone said that in the first few months the service was availale some skiers logged several hundred thousand to a few million vertical feet. To put that in perspective, the typical vertical rise on a mountain in Colorado and California is about 3,000 to 4,000 feet.

This ski season Epic Mix came to five  mountains including Vail, Beaver Creek, Breckenridge, Keystone and Heavenly covering a total of 17,000 acres or about 70 sqaure kilometers. Next season, North Star in Lake Tahoe California will be added.

There are about 160-180 pins that are awarded for exploring the mountain and completing various tasks.

Right now Vail Resorts is touting Epic Mix as an on mountain improvement, likening it to installing a new ski lift and haven't yet wrapped much marketing around the system. But considering the way Foursquare has gone, 3rd party promotions through Epic Mix might not be far behind.

With location tracking technology the question of privacy comes up, but Slone said that there are options on the Epic Mix site to turn sharing off, and skiers can get the RFID chip removed from their pass all together if privacy is a great concern.

From a technical side, Vail Resorts CIO Robert Urwiler said that the biggest challenge of Epic Mix was engineering everything from scratch. That included the development of hardware like the gantries to behind the scenes software to track skiers. But the entire system is possible because of UHF RFID chips in the lift tickets which can be read from up to 10 meters away.

Even though there's been a lot of work done on the system, the team hinted at more improvements for the next season.

They were vague on the details, but next year Epic Mix is going to integrate photography and video into the social networking app. Epic Mix is of course free to anyone who has an RFID enabled lift ticket, which doesn't cost any additional money.