Abstract: For e-commerce sites, in order to promote the development and win more benefits, attracting and keeping the customers becomes very important. One of the most useful technologies is recommendation algorithms. In e-commerce sites, sidebar advertising is a common form of recommendation, which can be divided into three main categories: content-based, collaborative filtering and hybrid recommendation algorithms. However, current recommendation algorithms are challenged by new application requirements, such as diversification, personalization, intelligentization and timeliness. It is urgent to design new algorithms to meet these requirements.

Key words: e-commerce, recommendation systems, diversification, personalization, intelligentization, timeliness