Lockerz, a social shopping site aimed at users between 13 to 30, announced that it’s making its first move into the mobile world today with the launch of a new smartphone website.

The Seattle startup launched the first version of its product back in February 2010. Founder and chief executive Kathy Savitt said that adding mobile support has been the number one demand by members — which isn’t surprising, since the site targets a young, tech-savvy audience, and also since one of Lockerz’ big features is the ability to earn discounts on merchandise that’s only available for a short period of time.

Lockerz allows users to earn points for doing what they normally do online (sharing videos and other content, as well as connecting with friends), which they then cash in for merchandise discounts. The concept seems to be resonating: Savitt said the site has 18 million users, 93 percent of whom are between 13 and 30.

The site should work on all major smartphone platforms. For now, it provides a limited set of features, which Savitt said the company will be expanding quickly. In this initial version, users will be able to view messages in their Lockerz Hallway and redeem their Lockerz points for merchandise. The second feature is the most important, Savitt said, because it means users no longer need to worry that they’re missing out on a great deal when they’re away from their computer, because they can still check out and redeem deals on their phone.

Lockerz was among the first wave of startups backed by Kleiner Perkins Caufield & Byers’ sFund for social startups. Liberty Media is also an investor.

Savitt said the company provides the first shopping experience aimed at Generation Z, which includes anyone born after 1992. It’s a demographic group that has incorporated technology into the fabric of its life, and it takes a “curatorial” approach to both shopping and content, she said: Basically, it’s a more aggressive version of what their older siblings already did with music.

“They’re turning the mall into a giant iPod,” Savitt said.

Not content to launch one mobile service today, Lockerz is also releasing an Android app for Plixi (formerly TweetPhoto), the photo-sharing app that it acquired last month.