Pew just released its 2013 data.
And 73% of adults (any age) are now on social networking sites.
Facebook and Instagram’s users are most likely to check daily. Pretty much every social network except Facebook has a niche (age, sex, urban location, etc.). If you’re thinking about branching out, these sorts of things are good to consider.
Read the full survey summary, with helpful graphics breaking down the data by social network: