ABSTRACT
Web 2.0 refers to a new form of using the World Wide Web in which users are encouraged to add value to applications as they operate them (AmerYahia and Halevy 2007). Examples of such applications include blogs, wikis, and social networks. The amount of data has increased exponentially, as well as the need to store, retrieve and manipulate it effectively. As a result, databases of a size that have never existed before have emerged. These databases can no longer be contained in one physical system, but must run in a distributed system.
