The JCIEL Plagiarism Detection Project acknowledges that:

the Internet is making it easier to copy other peoples work and with little or no alteration students can pass unoriginal material off as their own.

As an educator I am on the horns of a dilemma. I want to encourage interaction and cooperation amongst my students but whereabouts do you draw the line between cooperation and copying? Of course, the situation is further complicated by the ready availability of vast resources over the Internet. [Aside: I have even heard of teachers the ban the use of the 'net for resource discovery. How strange is that !?]. Ideally, assessments should be constructed in such a way to minimise the potential for plagiarism and yet don't overburden assessees with labour-intensive marking regimes . I must read up on the methods that work in this context.

I'm sorry if that last paragraph doesn't make sense. I only got three hours sleep last night and tiredness is catching up on me.