Web mining is the application of data mining techniques to extract knowledge from web data, including web documents, hyperlinks between documents, usage logs of web sites, etc. The process of extracting useful information from the contents of web document is data mining. Content data is the collection of facts a web page is designed to contain. It may consist of text, images, audio, video, or structured records such as lists and tables. The large and dynamic information source that is structurally complex and ever growing, the World Wide Web is fertile ground for data mining principles, or Web mining. Here, it defines the information retrieval and information extraction from web and making research for data mining.