21. A system comprising: a main memory having stored a reference dictionary file data structure, the reference dictionary file data structure including terms parsed from a plurality of documents stored in a document repository and terms parsed from a new document received by the system but not stored in the document repository, the terms parsed from the plurality of documents and the new document without regard to any user profile, the reference dictionary file data structure including a reference count value indicating a total number of documents that include a term, the total number of documents including documents stored in the document repository and the new document, the reference count value accessible by a user profile update operation for updating a user profile before the system determines whether the new document is relevant to any user, the terms parsed from the new document added to the reference dictionary file data structure as follows: when a term is included in the document statistics file data structure but not in the reference dictionary file data structure, the term is added to the reference dictionary file data structure and the reference count value in the reference dictionary file data structure associated with the term is initialized to one; when a term is included in both the document statistics file data structure and the reference dictionary file data structure, the reference count value in the reference dictionary file data structure associated with the term is incremented; and a mass storage having stored the document repository and a document index that indexes terms from documents stored in the document repository.
23. The system of claim 21 wherein the new document is stored in the document repository after the terms parsed from the new document are stored in the reference dictionary file data structure.