facebookFacebook posted second quarter earnings today, beating analyst expectations with $4 billion in revenue for the past three months ending June 30, which was up 39 percent year over year.

Over the last quarter, 1.49 billion people were actively using the site each month. An average of 968 million people logged into the social network daily in June, a 17 percent increase since last year. In the second quarter of 2014, daily average user rates grew 19 percent year over year, so the number of daily users is slowing down.

Facebook DAU q2 2015

However, advertisers are still turning to the site to get their messages out. More than $3.8 billion of Facebook’s revenue came from advertising, with more than three-quarters of that coming from mobile ads.

Costs also rose though, coming in at $2.8 billion and dragging profits down 8 percent year over year. More than 40 percent of Facebook’s costs were for research and development, more than double what it was a year ago. Those could be costs associated with VR platform Oculus and Facebook’s drone-enabled Internet.

“This was another strong quarter for our community,” said Facebook CEO Mark Zuckerberg. “Engagement across our family of apps keeps growing, and we remain focused on improving the quality of our services.”

Facebook shares dropped 3 percent in after-hours trading today as investors worried that the social network may be reaching its peak popularity.

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