Facebook (NASDAQ:FB) shares soared in after hours trading on Thursday, after an increase in mobile advertising saw it double fourth quarter profits.

The social networking site hit 1.59 billion users on Thursday and shocked Wall Street with a tenth consecutive quarter of growth. Its 2015 fourth quarter revenue was at $5.841 billion, with $0.79 earnings per share. These figures mean quarter on quarter growth was up 29.8%, up 51% on the same period last year.

The company also said that 80% of its advertising revenue in that period came from mobile advertising, up from 69% a year earlier.

Chief executive Mark Zuckerberg, who returned to work on Monday after two months of paternity leave, commented that 2015 was a “great year for Facebook”, saying “our community continued to grow and our business is thriving.”

Facebook’s growth strategy relies heavily on monetizing the developing world, more than tripling its revenue from the area over the last four years. Despite these users being on slow connections, old smartphones and not having much buying power, Facebook has convinced advertisers to pay to target them.

Facebook shares were up 12.12 percent in after hours trading.

Previous articleIs this the end of Apple’s growth?
Next articleUS rates remain unchanged as economy slows