There are 2.8 billion people on social media (that's 37% of the world's population!), and knowing who's doing what on which social platforms can be helpful to your business, according to a handy infographic by Tracx, a social media management platform.

The infographic consolidates user demographics across seven of the largest social networks: Facebook, YouTube, Instagram, Twitter, Pinterest, LinkedIn, and Reddit.

Over 50% of social media users are on only one or two platforms, the infographic points out, so businesses need to figure out the right place to find their audiences.

Facebook is best for reaching Millennials and Gen X, with the latter spending almost seven hours per week on social media, whereas Pinterest use is spread evenly across most age groups, the infographic explains.

And though 53% of Instagram users follow a brand, people referred by a Pinterest link are 10% more likely to make an e-commerce purchase than those referred by other social networks, the infographic claims.

To see who's on Twitter, why pushing sales on Reddit could backfire, and more info on social media, check out the infographic: