Ever wondered how many people use your favorite social networking sites, app or digital service? You’re in luck! In my agency days, I often found when writing proposal, presentations, etc, that some of the simplest of stats like “how many people use” something are next to impossible to find.
http://expandedramblings.com/index.php/resource-how-many-people-use-the-top-social-media/
How Many People Use 800+ of the Top Social Networks, Apps and Digital Services?
811