Facebook has released its results for the fourth quarter of 2013 and the numbers are strong. It posted $2.59 billion in revenue and earnings of 31 cents a share. Analysts were looking for Facebook to pull in $2.33 billion in revenue with earnings of 27 cents a share. That compares to $1.59 billion and 17 cents a share for the same period last year. It's also a touch above the $2.02 billion and 25 cents a share Facebook notched last quarter. The stock is currently up slightly in after-hours trading.

Most notably, the company reported that 53 percent of its revenues now come from mobile advertising. That is a big milestone for Facebook, which stumbled badly during its IPO over concerns that it was struggling to migrate its ad business from desktop to mobile along with its users. At IPO time, Facebook hadn't yet made a dime from its mobile business. The company now has nearly a billion monthly active mobile users, jumping from 680 million monthly mobile active users last year to 945 million monthly mobile active users in the fourth quarter of 2013. Mobile daily active users were 556 million on average for December, 2013, an increase of 49 percent year over year. In grand total across all platforms, a whopping 1.228 billion people use Facebook every month.

It was nine months ago that Mark Zuckerberg introduced Facebook Home, an ambitious attempt to have the social network become the operating layer for mobile devices. That effort seems to have largely been a flop. The company's biggest success of 2013 was Messenger, a slick, focused app that has stayed near the top of the charts. Facebook is reportedly planning to continue the trend with a suite of standalone apps this year, perhaps aiming to take over default functions on mobile such as your contacts and calendar.