6. The method of claim 1 further comprising: generating a plurality of copies of the electronic learning materials; and associating at least one of the identification strings with at least a portion of each copy of the electronic learning materials, wherein the identification string associated with a portion of one copy of the electronic learning materials is different from the identification string associated with same knowledge items of other copies of the electronic learning materials.
6. The method of claim 1 further comprising: generating a plurality of copies of the electronic learning materials; and associating at least one of the identification strings with at least a portion of each copy of the electronic learning materials, wherein the identification string associated with a portion of one copy of the electronic learning materials is different from the identification string associated with same knowledge items of other copies of the electronic learning materials. 7. The method of claim 6 wherein the identification string associated with one copy of the electronic learning materials is different from the identification strings associated with other copies of the electronic learning materials.