10. The ability to create and update content leads to the collaborative work of many rather than just a few web authors. In wikis, users may extend, undo and redo each other's work. In blogs, posts and the comments of individuals build up over time.
12. Categorization of content by users adding "tags" - short, usually one-word descriptions = to facilitate searching, without dependence on pre-made categories. Collections of tags created by many users within a single system may be referred to as "folksonomies"
21. What is Social Networking A social network service focuses on building and reflecting of social networks or social relations among people, e.g., who share interests and/or activities. A social network service essentially consists of a representation of each user (often a profile), his/her social links, and a variety of additional services. Most social network services are web based and provide means for users to interact over the Internet, such as e-mail and instant messaging. Social networking sites allow users share ideas, activities, events, and interests within their individual networks.
25. Digg Digg is a social news website made for people to discover and share content from anywhere on the Internet, by submitting links and stories, and voting and commenting on submitted links and stories. Delicious Delicious (formerly del.icio.us, pronounced "delicious") is a social bookmarking web service for storing, sharing, and discovering web bookmarks.