Because of the lack of a uniform schema for Web documents and the least amount and dynamics of Web data, both the effectiveness and efficiency of information management and retrieval of Web data is often unsatisfactory when using conventional techniques of data management. Web community, defined as a set of web-based documents with its own logical structure, is a flexible and efficient approach to support information seeking and applying a variety of applications. They also detail the necessary preliminary to understand the algorithms presented, and they discuss several successful existing applications. Researchers and students in information retrieval and Web search find in all the necessary basics and methods to create and understand Web communities.