Payments and other fees revenue for the fourth quarter was $256 million, flat year-over-year after a $66 million adjustment because the company recognised revenue from four months of transactions for accounting reasons.

Overall, Facebook's revenue for the quarter was up 40% to $1.585 billion. Much of this was driven by a doubling of mobile advertising revenue, which now accounts for 23% of all ad money.

The social network is finding it more difficult to make money from the mobile revolution when it comes to payments, though. CFO David Ebersman told a conference call that while the firm is seeing strong growth of its platform in games on Android and iOS, "at this point we don't have any payment integrations with these mobile games".

However, adds Ebersman "our belief is that if we can help game developers to grow users engagement and monetization it puts us in an interesting position to consider future financial relationships."

Of the $256 million payments revenue, the vast majority was down to in-game Facebook Credits. The Gifts service - launched late last year in the US as a way for users to buy digital and physical goods for friends - contributed revenues of just $5 million.

"The focus right now is to figure out what the right product is. We think if done well, Gifts can be very natural and positive part of the Facebook experience," says Ebersam.