The growth team was formed in late 2007, when Zuckerberg decided expansion was so important that it warranted a unit with its own resources. The site was approaching 100 million members, but its growth rate had cooled. […]
Within two years of its creation, the team had expanded Facebook’s roster of users sevenfold, to 360 million. […]
Recently, his team was renamed GEM—an acronym for growth, engagement, and mobile. Facebook’s new priority is keeping existing members active and logging in from mobile devices.
— Chasing Facebook’s Next Billion Users