13. The system of claim 12 , wherein: the first pre-defined character position within the word at the corresponding starting word position is a first letter of the word at the corresponding starting word position; and the second pre-defined character position within the word that is offset from the corresponding starting word position by the pre-defined number of words is a first letter of the word that is offset from the corresponding starting word position.
13. The system of claim 12 , wherein: the first pre-defined character position within the word at the corresponding starting word position is a first letter of the word at the corresponding starting word position; and the second pre-defined character position within the word that is offset from the corresponding starting word position by the pre-defined number of words is a first letter of the word that is offset from the corresponding starting word position. 15. The system of claim 13 , wherein the different starting word positions include positions of a contiguous sequence of words within the text of the electronic document.