GradeGuru seems to take this to a new level. This is a McGraw-Hill Education start-up which appears to combine social networking with note-taking (see GradeGuru - Facebook for Learning). Students submit their notes, which can then be searched and rated. There is a reward system in place, so that high ratings earn extra points, which can be traded in for rewards.
In a sentence: GradeGuru is a notes sharing website where students who need relevant, course-specific study notes can find them, and where students who have study materials can share them to get rewarded with cool stuff and recognition.
So, what's the difference between this and an essay-mill? Well, students have to register with their university email address, and give their affiliation. Hidden in the depths of the faq, I found the following:
Isn't sharing a form of plagiarism?
A:No, GradeGuru is to be used for reference purposes. We do not encourage copying or plagiarism of any form. In the near term we plan to partner with anti-plagiarism tool providers to ensure our site is not misused and that our contributors are encouraged to share the way the got to their answers, not just the answers themselves so as to prevent any form of cheating.
It certainly raises some concerns, but is it any different to writing in black ink?