OK. My idea was to have the students upload their own Powerpoint presentations to a slidesharing website like slideshare.net.  Using my google email account, I created attached accounts by adding the computer name to my name, so that the students could log in to slideshare using their computer name.  So far, so good.  The upload is no problem, and because these slideshows are small in size, the upload does not take log.  Herein is my problem.  I want the teachers to be able to easily find the slideshows of their students, without pulling up anybody elses.  There are some inappropriate things on this website, and I do not want students, parents, or teachers to accidently come across anything else.  I am having a very hard time coming up with a filename or tags that will only pull up a certain group of slideshows.  If anyone else has encountered this problem, I would be most grateful to hear your advice on the matter.  In the meantime, I will continue to try to make this work.