I work at The University of Northampton (UK), and we use http://www.turnitin.com/static/home.html[^]. I don't know about the back end, but I'd like to make some general comments. The point of this is not just to catch plagiarisers (buying off the net), but also to protect student work from being stolen and passed off as their own, in a way providing an intellectual property right/copyrighting system free of charge to the students. If you submit the same work for a different assignment, but the registered owner is the same, there isn't a problem as you own the work. We've had two stories about the use of these systems: The first is that someone submitted some work to Turnitin that showed up as plagiarised from Google, the student resubmitted, and this time accidentally included the receipt they were issued from the place they bought the work!! (they failed their year). The second, and this is where it can go very wrong, someone wrote their assignment, someone else stole it from them and submitted it to Turnitin before the originator did, the originator submitted it and got done for plagiarising his own work!!! The investigation did reveal the truth, but showed that in order to protect your own work, you should submit it as soon as you are ready to. It is an evolving technology, but plagiarism is a cultural quirk. Chinese and Japanese students are brought up to repeat the words of their teachers, and we go to great lengths to teach them that it is fine to do that, but Western education requires you to add your own words to it, and also to reference your sources. I thought nicking code was fine as long as you honoured the originator? ;)