Social networking
From DigitalJargonBuster
A social network is a social structure that allows users to communicate and share content and information such as messages, photos and videos. These come in many forms, ranging from personal websites for sending messages to friends, to professional collaboration applications where users can share and discuss their ideas; they can be open to any user or members-only.
Due to the extreme popularity of social networking, there are now very many websites on the internet dedicated to it such as MySpace, YouTube, Flickr and Facebook.