A new type of website.

Or just a new word. "Community" was the word used to describe The WELL and later GeoCities. "Web2.0" – coined by O'Reilly to launch a conference and the idea that the web was back after the Bubble – was used for the first generation of "new" services, like Flickr, del.icio.us and Last.fm. But when Friendster, MySpace and then Facebook and Twitter came along, they were all immediately called "social networks".

The notion of social networks comes from academia. In the 1920s, the idea that the world was "shrinking" due to the ever-increasing connectedness of human beings became popular. The Hungarian Frigyes Karinthy [1] went a step further and said that any two individuals could be connected through at most five acquaintances – hence the famous 6 degrees of separation – starting from their "social network".