Want feedback on a paper, business document or other writing? Kibin is an editing community where volunteer editors will proofread and offer unbiased feedback for free.
The service is very easy to use. Upload your (doc, rtf, or txt) file and in about 24 hours you'll get your paper returned with edits/comments in the Kibin dashboard. (If you're in a hurry and need a guarantee that your editing will be done in 24 hours, you can opt to pay the $US0.01 per word, but otherwise the service is free.) You can become a volunteer editor yourself.
In my simple four-paragraph test, the Kibin editor made some helpful suggestions. It's nice to have another pair of eyes check your writing.