Facebook has announced its first-quarter 2014 results, subsequently revealing it had 1.28 billion monthly active users and over 1 billion monthly active mobile users during the quarter.

The social network therefore crossed the 1 billion milestone, in regards to monthly active mobile users anyway, for the very first time. In January, Facebook said it had 945 million monthly mobile active users during Q4 2013, and that was also a large increase from 680 million users in the same quarter from a year earlier.

Apart from usage numbers, Facebook reported revenues of $2.5 billion and earnings per share of 34 cents. In the year-ago quarter, Facebook reported $1.45 billion in revenues and earnings of 9 cents per share. Facebook also said it now makes $5.18 in annual advertising revenue per user. That's something - besides mobile numbers - investors will be happy about.

Analysts largely expected a 24-cent profit per share on $2.4 billion in revenues. Mobile ad revenues appear to have helped Facebook beat those expectations. Specifically, Facebook hit 59 per cent of ad sales, which is up from 30 per cent a year ago, and the company's ad sales spiked 82 per cent to $2.27 billion.

READ: Facebook nears 1bn mobile monthly active users

Now that Facebook is a public company, it will likely take advantage of its booming mobile audience by introducing more mobile apps capable of pushing ads. That said, Facebook reportedly plans to launch a suite of standalone apps in 2014.