|Flickr CC Horia Varlan|
I've personally received feedback on all sorts of materials - blog posts, articles, web content, essays for job applications, resumes, and cover letters. It's a fantastic service, and it's free! Documents cannot be larger than 1400 KB, but my 450 word article was only 19 KB, for some perspective.
I think this service could help busy indiepreneurs who need a second set of eyes. Non-profits may benefit from sending grant proposals for proofreading.
I hope this helps! Let me know if you use the service.
I'm taking a long weekend to visit my sister, so my work week is ending today. Happy Thriday!