Facebook recently launched a new test in which they're allowing users to buy products from ads and News Feed Pages without having to leave the site. It's available to Facebook mobile or desktop users and is open to a few small and medium-sized businesses in the US free of charge according to a news release on the matter.

The social network said the feature was designed with privacy in mind. Users can either complete their purchase with credit or debit card information they have on file with Facebook, enter new payment details to save for later use or complete the checkout process without saving anything.

We're told that none of the credit or debit card information entered is shared with other advertisers.

While the new service will no doubt offer a level of convenience for potential shoppers, the winner here is Facebook. Because buyers won't have to leave Facebook to make a purchase, they'll be staying on the social network for longer periods of time. Such data can be invaluable when it comes to selling advertising space.

What's more, it would stand to reason that buyers would be more inclined to share news of their purchase with friends since they are already on the site.

Facebook isn't the only social network getting in on the e-commerce action. Twitter launched a similar e-commerce partnership with Amazon back in May. Although buyers can't actually check out via Twitter, they can set stuff aside for purchase later. Think of it as a bookmarking service for Amazon via Twitter.

Facebook promised to share more information as they gather feedback.