Internet-based applications that allow the exchange of content created by their users.
Social media can be classified in different types: (1) social networking sites (e.g., Facebook, LinkedIn, Instagram); (2) blogs, including microblogs (e.g., Twitter); (3) content communities (e.g., YouTube, Flickr, Pinterest); (4) collaborative projects (e.g., Wikipedia); (5) virtual social worlds (e.g., Second Life) and (6) virtual game worlds (e.g., Sims).