The move from traditional to online services and the spectacular increase in the number of online customers bring great challenges to the field. Analysing the Internet flow, valuable insights about the traffic coming and leaving an e-commerce site can be found, helping them to become more effective and increasing their competitiveness. This is what Web mining does, as it deals with the mining of remarkable knowledge from the Internet, studying the way users interact. Web mining is used in e-commerce to find the browsing habits of customers, helping in understanding their preferences. This paper examines the main processes of data mining (Web Content, Web Structure and Web Usage information) and the various types of web data mining technologies, emphasizing their use in the online business. An overview of the latest developments is presented and the main challenges are outlined. As a final point, possible perspectives of web data mining in the e-business domain are analysed.