[url]http://www.washingtonpost.com/wp-dyn/content/article/2007/03/28/AR2007032802038.html[/url]
Apparently they check students work against a database and tell teachers if it was copied or not. Only thing is they then hold a copy of the document submitted and use it later on. Oh noes!
Why doesn't the RIAA go after them, if they have any song lyrics in the database it could mean a whole lot of money.