• YouTube - which allows members to upload videos for everybody to see and vote on their popularity;
• social networking sites, such as Facebook and MySpace, with hundreds of millions of users which allow subscribers to create web spaces where they can share their thoughts, music, videos and pictures;
• Flickr's photo collecting, tagging, and distribution service;
• sites like del.icio.us that allow users to bookmark favourite sites and share those bookmarks with others;
• free Audacity software for recording and editing sounds that allow users to record talk and music which, when combined with RSS, become podcasting; and
• tools such as CiteULike allow scholars to share their personal bookmarks (Downes, 2005; Virkus, 2008).

However, the above are just some examples. These types of sites have become incredibly popular. Reding (2006) notes that blogs have doubled every five months for the last two years; social networking web sites usage is multiplying year on year; over the past three years peer-to-peer has become the largest source of traffic on the internet and FON, the wifi-sharing network, has become the largest wifi network in the world in just one year (http://www.fon.com/en/info/whatsFon). The rapid evolution of Web 2.0 applications offers rich user experiences where the process of knowing is a community-based, collaborative endeavour (Alexander, 2006; Virkus, 2008).

However, in 2009 Focus.com made the illustration The Boom of Social Sites, showing the development of the social networking tools. They showed that Classmates.com was the first social networking tool, created in 1995. But Kaplan and Haenlein (2010) set the genesis of these social networking tools even earlier in time: "By 1979, Tom Truscott and Jim Ellis from Duke University had created the Usenet (established in 1980), a worldwide discussion system that allowed Internet users to post public messages. Yet, the era of Social Media as we understand it today probably started about 20 years earlier, when Bruce and Susan Abelson founded Open Diary [in 1998] an early social networking site that brought together online diary writers into one community" (p. 2).

Please look at Social Networking Tools Simplified. You can also look at the list of social networking websites to learn more.