World Wide Web (WWW) is the largest source of information. Most of the data on the web is dynamic and is in unstructured form. It is becoming difficult to get the relevant data from the web. Data mining is the field of computer science which is used to extract knowledge from very large amount of data. Web mining is the application of data mining, which implements various techniques of data mining to get the efficient knowledge from the web data. This paper presents an overview of various techniques that has been used for web content mining including images, audio, video and semi-structured contents like HTML and XML.