" 'Impossible!' you say? Look, we can't grade the essays for you, but we can reduce the repetitive, inefficient manual labor involved - and in doing so we open up a new world of invaluable student data."
This is in Beta version so it is being offered for free at the moment. It sounds like it will eventually become a paid service - but maybe it's worth the price for those of you that grade a lot of rubric-based essays.