1. A custom electronic learning system, comprising: at least one computing device including: a system for converting a knowledge object stored in at least one electronic file in the at least one computing device into a set of knowledge atoms stored in a tree structure in the at least one computing device, each knowledge atom representing an elementary piece of information that is contained in the knowledge object; and a system for generating an electronic learning object stored in at least one electronic file for presentation to a user based on a set of user characteristics for the user and the set of knowledge atoms, each user characteristic comprising information associated with the user that affects at least one of: a format or a display of the custom electronic learning object for the user.