Facebook has more daily active users on mobile than desktop

"CEO Mark Zuckerberg observed that the network now has more daily active users on mobile than on desktop. "Soon we'll have more revenue on mobile than on desktop as well," he said.
Considering the global patterns of Facebook usage, demonstrating mobile ad revenue acceleration is critical for the company. There were 819 million mobile monthly active users on Facebook as of June 30, up 51% over the previous year. That's 71% of the total who access the social network at least once a month.
CEO Mark Zuckerberg observed that the network now has more daily active users on mobile than on desktop. "Soon we'll have more revenue on mobile than on desktop as well," he said."

Source:  AdAge, 24th July 2013