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1 billion people used Facebook on Monday

A 3D plastic representation of the Facebook logo is seen in this illustration in Zenica, Bosnia and Herzegovina, May 13, 2015. REUTERS/Dado Ruvic

Talk about a social network: Almost one out of every seven people on Earth used Facebook (FB) on Monday.

Chief executive Mark Zuckerberg wrote in a Facebook post that 1 billion people logged into the world's biggest social network.

"This was the first time we reached this milestone, and it's just the beginning of connecting the whole world," Zuckerberg wrote in the blog post.

The Menlo Park, Calif.-based company said last month that it had 968 million daily active users in June, which represented a 17% increase from the same month in 2014. Looking more broadly, 1.49 billion people log on to Facebook at least once a month, as of June.

The company's shares are up 15% for 2015, zooming by the technology sector, which has posted losses of 2.5% for the year, according to data from FactSet Research Systems.