This handy infographic share key demographics for all the key social media sites. The stats help break some assumptions that I have heard from marketers such as that people on higher incomes do not use social media; or that younger people (18-29) don’t use Twitter. Infographic via SproutSocial.
These demographics are just one factor in deciding where you target your activity. With Twitter, for example, whilst the numbers may not be as high there is a higher number of influencers including most journalists who use this social network as a source for stories. Other factors will be accesibility, SnapChat may have a huge number of <25’s but how accesible are they through the service?