Good infographic here comparing the Top 10 social networking sites. It says they account for closing on 1.5 billion users between them, but more than a third of that, of course, belongs to one company. As well as the big names of Facebook and Twitter it looks at some of the smaller ones that still have millions of members each. The surprise is maybe that MySpace still boasts 100 million members.
It estimates that seven out of 10 web users are active on at least one social network and that nine out of 10 marketers use social networking to promote their business in some way. Take a look.