Currently, e-commerce sites are basically using category navigations and attribute navigations to provide navigation information to users. 
Most category navigations are represented by tree structures.  The users click contents in a category navigation guide to narrow a search, and then use an attribute navigation to precisely find the user's desired products. 
Compared to other types of navigations, the attribute navigation is more diversified.  However, no matter whether it is generalized or personalized attribute navigation, identifiers displayed by the conventional attribute navigation are fixed attributes of the products and such identifiers are labeled on the products so that the users may find the products through navigation.  The identifiers relate to information provided by sellers when the sellers upload the products.  The identifiers later pass manual review and are finally labeled on the products.  Content displayed by the attribute navigation are also identifiers that describe the fixed attributes of the products.  In the example of clothing products, the conventional attribute navigation can only display descriptions of the fixed attributes of clothes such as a brand, a material, a size, a basic style. 
In the above conventional techniques, the form of identifiers of product labels is too simplified to benefit the user to choose products.  Contents displayed at the navigation guide are just identifiers that describe the fixed attributes of the products.  Some identifiers are not easy for the users to understand and cannot directly reflect the users' desires.  Currently, the users have attention to the products from more and more perspectives of the products.  There are also more and more product types and quantities.  Information volume of each product is also larger and larger.  It is important to classify such large amount of product information from the attention perspectives of the users.