Twitter reported its first earnings as a public company yesterday, revealing that sales more than doubled from a year ago, though it still hasn't managed to turn a profit.

Revenue for the quarter ended December 31 was $243 million, up 116% from the same quarter a year earlier, Twitter said. That was far higher than the $218 million analysts had been expecting, according to a poll by Thomson Reuters.

Its loss was a hefty $511 million, much greater than its loss of $8.71 million in the fourth quarter of 2012. Excluding share-based compensation and other adjustments, it would have made a profit of $0.02 per share, again better than analysts had expected.

"Twitter finished a great year with our strongest financial quarter to date," CEO Dick Costolo.

Still, investors reacted by pushing its shares down nearly 10% in trading after hours, to $59.60 at the time of this report.

The company ended the year with 241 million monthly active users, up 30% from the fourth quarter of 2012. Despite the increase, it lags far behind Facebook, which has passed 1.2 billion monthly active users.

Twitter's advertising revenue totalled $220 million for the quarter, up 121% from a year earlier. More than 75% of its ad sales were from ads placed on mobile devices, showing Twitter's ability to monetise its site on a critical platform.

It was Twitter's first earnings report since the company went public late last year at $45 a share. Its IPO documents showed at the time that the company was growing fast but losing money.

Since the IPO, which was viewed as a success, the company has faced questions about its ability to maintain its growth rate and become a more "mainstream" service like Facebook.

One of Twitter's largest advertising products is its promoted tweets, which allow marketers to place sponsored tweets in users' streams. Twitter only charges marketers when people click on the tweet or follow the promoted account, however.

For the full year, Twitter's sales grew by 110%, to $665 million. Its net loss for the year was $645 million.