One of, if not the first social media network based ont he internet was established in 1997. The founders of sixdegrees hoped that through a series of connections, everyone in the world would be connected on the webpage. Recruitment was done through invite only. Users could create profiles and list their interests on their page.
For other breakthroughs in social networking, see:
Source: David Kirkpatrick, The Facebook Effect: The Inside Story of the Company That Is Connecting the World (New York: Simon and Schuster, 2011), 67-68.