Around one in seven human beings on earth are now active Facebook users, the social network’s leader, Mark Zuckerberg, claimed on Thursday, announcing a major symbolic milestone for the company.

“This morning, there are more than one billion people using Facebook actively each month,” Zuckerberg wrote in a blog posting on his Facebook page.

In an interview with the NBC “Today” program, Zuckerberg admitted that his company is in a “tough cycle” following its first public stock offering earlier this year described widely as disastrous.

But he insisted Facebook’s gaze was fixed firmly on the future, which he said would involve more emphasis on mobile internet technologies and applications.

“The future is really going to be about mobile and the opportunities for growth there,” Zuckerberg said.

On Wednesday, Facebook announced that it would begin testing a pay service allowing users to “promote” their postings on the network.

“The test started first in New Zealand in May and gradually rolled out to people in more than 20 countries,” a Facebook engineer wrote on his page. “It will now appear to people in the US.”

Under the plan, users would ensure that their postings were displayed more prominently in the feed that delivers those postings to Facebook friends.

“One of the ways Facebook — which has always gone by the slogan “It’s free and always will be” — is monetizing its platform is by allowing users to pay to promote their posts,” the New York Daily News said in a report.

Such a paid promotional service has been available to companies since May.