Though Pinterest, currently valued at $3.8 billion, is not technically an e-commerce site, it has the potential to become a major sales driver for online retailers.

Discussion of Pinterest's potential as a social commerce platform began early, and the site's conversion rates have quickly outpaced those of Twitter and Facebook. A Shopify study from last May shows that while Facebook drives more traffic, visitors from Pinterest are 10 percent more likely to actually make a purchase. Additionally, Pinners on average spend twice the amount that a shopper referred from Facebook would spend.

Pinterest's viability as a social commerce platform has only grown since then, recent studies have shown. According to Business Insider, Pinterest accounted for 23 percent of global, social-mediated e-commerce sales in the second quarter of 2013. As recently as 2012, it only accounted for 2 percent.

This week, social marketing platform Piqora sent us a study conducted by two former Google engineers, showing how the dollar value of a Pin has grown exponentially. On average, a Pin generates 78 cents in sales, up 25 percent from the fourth quarter of 2012.

Even more interesting is that a Pin tends to drive sales for a much longer period than a post on another social network does. According to Piqora, 50 percent of visits to sites referred from Pinterest happen 3.5 months after the original Pin, because Pins can be discovered long after they're created. The same cannot be said of a sites like Facebook. So how does this translate into sales? Fifty percent of orders happen two and a half months or more after the initial Pin. It makes sense: when a Pin is popular, it continues to get discovered, and chances are that means it's something worth buying. That means that a popular Pin could generate sales for months, assuming that product remains in stock.

The study also found that purchases from Pinterest spike on Mondays. Piqora speculates this is because people browse on the weekends and pull the trigger on Mondays after doing more research and "consulting with their spouses."

Brands are obviously taking advantage of the power of a Pin. More sites have Pin It buttons and more Pins actually lead to product pages where the item can be purchased.

However, there are still the same obstacles to Pinterest's e-commerce potential that there always have been, which is brands' control. Not everyone is going to link their Pins to points of purchase, and by nature Pinterest is not structured like your typical e-commerce site. It will never be as easy to find what you're looking for (if it's something specific) on Pinterest as it will on, say, Amazon. It's perhaps better for discovering something you didn't even know you wanted.

Still, it's not something brands or marketers should ignore. Pinterest isn't ignoring it either -- it recently began experimenting with sponsored Pins and has integrated e-commerce into its just-launched Japanese site. It's presumably only a matter of time before Pinterest facilitates e-commerce stateside as well.