14. The method of claim 1 including, in a case that a user expresses an interest or expertise that has a corresponding encyclopedic document, using Wikipedia as a knowledge base, to form vector space matching with other objects.
14. The method of claim 1 including, in a case that a user expresses an interest or expertise that has a corresponding encyclopedic document, using Wikipedia as a knowledge base, to form vector space matching with other objects. 16. The method of claim 14 including, when users provided information about their interests directly, using document content, in particular term frequency, to represent their interests; and, when interests and expertise are expressed indirectly (and continuously, through third party data providers), we chose the document category representation.