Facebook's strong growth continued into the fourth quarter of 2015, with the company posted record earnings for the quarter and the year. The company earned $3.69 billion on $17.93 billion in revenue in 2015; revenue was up 44 percent from 2014. On average, 1.04 billion people use Facebook every day, up 17 percent from the previous year. Close to 1 billion people — 934 million — use Facebook every day on a mobile device, up 25 percent. "2015 was a great year for Facebook," CEO Mark Zuckerberg said in a statement. "Our community continued to grow and our business is thriving. We continue to invest in better serving our community, building our business, and connecting the world."

The company's strong growth reflects its success not just in growing its massive user base but in profiting from it. Facebook, which initially struggled with the move to mobile devices, is now among the industry leaders. Its combination of traditional targeted display ads and ads that prompt you to install other apps have made it increasingly profitable for each user it attracts. In its most recent quarter the company earned $13.54 for every user, up from $9 in the same quarter last year. (A small fraction of that number comes from payments and other fees Facebook charges.)