The first social networking website was Classmates.com, which began in 1995. Other sites followed, including SixDegrees.com, which began in 1997, Epinions which introduced the circle of trust in 1999, followed by European equivalents Ciao.com, Dooyoo and ToLuna. It was not until 2001 that websites using the Circle of Friends online social networks started appearing. This form of social networking, widely used in virtual communities, became particularly popular in 2002 and flourished with the advent of a website called Friendster. There are over 200 social networking sites. The popularity of these sites rapidly grew, and by 2005 MySpace was getting more page views than Google.  Google has a social network called orkut, launched in 2004. Social networking began to be seen as a component of internet strategy at around the same time: in March 2005 Yahoo launched Yahoo! 360°, their entry into the field, and in July 2006 News Corporation bought MySpace. .
In these communities, an initial set of founders sends out messages inviting members of their own personal networks to join the site. New members repeat the process, growing the total number of members and links in the network. Sites then offer features such as automatic address book updates, viewable profiles, the ability to form new links through "introduction services," and other forms of online social connections. Social networks can also be organized around business connections, as in the case of LinkedIn.
Blended networking is an approach to social networking that combines both offline elements (face-to-face events) and online elements. MySpace, for example, builds on independent music and party scenes, and Facebook mirrors a college community. The newest social networks on the Internet are becoming more focused on niches such as art, tennis, football (soccer), golf, cars, dog owners, and even cosmetic surgery. See also Social computing.
Most of the social networks on the internet are public, allowing anyone to join. Organizations, such as large companies, also have access to private social networking applications, known as Enterprise Relationship Management. They install these applications on their own servers and enable employees to share their networks of contacts and relationships to outside people and companies.
A recent development of social network is the integration of marketplace element in it, known as the Social Marketplace