You may know of Turn-it-In, the paper checking software.  Now, what I need to know is if previous papers I've handed in are in the database.  I need to write an essay, and in order to do so I'm going to combine two previous essays I've written.  One or more may have gone through Turn-it-In, although I'm not sure (do they have to tell you before hand?). Because, if it does come up, the nature of the software makes it hard to prove that I actually wrote the essays it's comparing it to.