Pinterest is growing fast, and 80% of the site's users are women ages 25-44.

Laura Skelton, owner of Prix-Prix, told me about Pinterest months ago when we met up one chilly Chicago morning for brunch. "Have you tried Pinterest?" she asked me with a glint of excitement in her eyes. I shook my head no. "Try it out, but be careful, you'll get addicted." I am always wary of that caveat because I do end up getting addicted. I decided to stop by just to see what was up. I registered for an account and then left. Everything looked too pretty. Then, a few months later, I started receiving a slew of notifications: "So and so is following you on Pinterest." It was around then that Pinterest blew up.

AdAge's David Teicher wrote about how Pinterest is driving traffic to sites like design magazine RealSimple. But more importantly, he writes, "the true potential in Pinterest may be in its ability to impact purchases, which is why retailers like Etsy, Nordstrom, and Lands' End have taken to developing a presence on, and strategy for, this new platform."

It's easy for retailers to create visual storefronts that emulate the clean, easy-to-browse features of tablet commerce. "We view this [Pinterest] as another way to engage with customers rather than marketing," Nordstrom's social media manager Shauna Causey told AdAge. "Images are a great way to share ideas and trends in the retail social media landscape." Oh, and then there's the ease of commenting on photos of hot runway models who are wearing sexy, expensive clothing.

We've written about how Facebook is trying to make social commerce work. Or, in less market-y terms, how Facebook is trying to become a mall. The launch of Timeline social apps seemed like a step in that direction, as it included fashion and shopping apps from Fab, Oodle, Pose and Lyst.

Still, Pinterest is showing increasingly strong signs that it is a more effective as a social commerce platform. New data from Monetate show that referral traffic from Pinterest to the websites of five specialty apparel retailers jumped 389% from July-December 2011.

Only 1% of Facebook "fans" engage with brands. Will this change? Right now you can buy donuts and earn Facebook credits through a new loyalty program from Plink. Last year Facebook announced integration with eBay.

Still, Facebook wrongly conflates the social graph with the interest graph, assuming that if your friends like it you will, too. Facebook is organized around the social graph first, whereas Pinterest is focused on the interest graph. Sure, your Facebook friends are probably all on Pinterest, but the true focus of Pinterest is not social. It's interest. Users organize around interests, making Pinterest a natural space for shopping. The visual focus doesn't hurt that, either. Facebook is too focused on the user experience and social, which ends up making it a difficult space for shopping. Plus there's that whole, you know, user distrust over Facebook's long-standing privacy issues, including EPIC's latest request that the FTC look into Facebook Timeline's possible privacy violations.

For more on how businesses are using Pinterest, check out this story by ReadWriteWeb's Dave Copeland.