Abstract: The Long Tail Theory suggests that the Internet contributes greatly to the development of the niche market. However, some recent researches believe that the there is ready sale for popular products online. In order to verify the different performances of online vendors in the two types of markets, this paper conducts an analysis on the sales data of more than 641 thousand kinds of products sold by 791 shops on Taobao. The results show that online sales are influenced by such factors as reputation, product variety, price, public praise and recommendations. And these influences also present significant difference in the niche market and popular market. Of which, the factors of reputation, product diversity, price, and public praise have a greater impact on the sales of niche products. The recommendations based on past data have a positive effect on the sales of popular products and a negative effect on the sales of niche products. In addition, it is found that online sales have the advantage of backwardness.

Key words: Long Tail Theory; niche products; popular products; recommendation systems; Taobao.com