10. The document serving system of claim 9 , wherein the data storage system stores a value (vp) associated with the user and with the first term, and the value determined for the first term is a function of said value stored in the data storage system (vp), the determined action value (a), and the first term value (vd1) which equals the number of times the term appears in the document.
9. The document serving system of claim 8 , wherein fee-each term value for a term equals the number of times the term appears in the document.