According to Kaplan and Haenlein there are six different types of social media: collaborative projects (e.g., Wikipedia), blogs and microblogs (e.g., Twitter), content communities (e.g., YouTube), social networking sites (e.g., Facebook), virtual game worlds (e.g., World of Warcraft), and virtual social worlds (e.g. Second Life).
This is a classification of the social media types: collaborative projects
blogs/microblogs
content communities
social networking sites
virtual game worlds
virtual social worlds