Pretty cool free online essay grader

I came across a website http://www.paperrater.com.  It's a little like the Vantage computerized essay grading program that was popular several years back in LAUSD.  While I normally abhor the idea of computers grading essays (though studies have found that it's becoming much more accurate), I see no reason why students can't use it to help edit and revise their own papers.  While I wouldn't use it as a tool for summative assessment, anything that will help students during the writing process is OK in my book.