Feb 4, 2011 11:31 GMT  ·  By

Facebook recently announced that it will be making Credits mandatory for game developers on the site. But it's also expanding the scope and functionality of the virtual currency, with two new features available now to developers, group buying and in-app purchases. The two features are designed to increase engagement and should mean better conversion and more money spent in the apps.

"Today, we’re introducing two features for developers that use Facebook Credits as the primary virtual currency within their games: buy with friends and frictionless payments," Prashant Fuloria, a product management director at Facebook, announced.

"These features enhance the user experience when credits are integrated as the in-game currency and premium virtual goods are priced in credits," he added.

Buy with friends is exactly what it sounds like, it enables users to share special offers with their friends for discounts. If more users end up buying an item, because they found out about it from friends, they all get a better price.

If this sounds familiar it's because the method has proven hugely popular for Groupon, the group buying site. But, before the "Facebook is challenging Groupon" rumors start, the social network limits the feature to virtual goods so there's nothing to worry about, at least not yet.

"Buy with friends has performed well in our tests -- more than half of people who were offered a deal in-game decided to share it with their friends, and the engagement and conversion rates on the resulting posts were also strong," Facebook explains.

Frictionless payments is rather self-explanatory as well, it enables users to buy items with Facebook Credits directly in the app or game they are using.

Regularly, purchases have to go through the Credits interface, taking players out of the game. Frictionless payments enable developers to allow users to make small purchases, 30 Credits or less, inside the app, in a few steps.