21. The computer-implemented method for building a user profile of claim 16 , wherein building the user profile includes deriving a user cluster of related users.
21. The computer-implemented method for building a user profile of claim 16 , wherein building the user profile includes deriving a user cluster of related users. 26. The computer-implemented method for building a user profile of claim 21 , wherein building the user profile further includes: computing a similarity measure between the user profile of the user of the electronic document and other user profiles of the cluster of related users; and building a group of related users based upon the user profile of the user of the electronic document and the user profiles of the cluster of related users.