I have not been able to determine from the posts whether the quotefinder feature still exists. It would be helpful, if it is no longer in existence, to have some sort of message to indicate this. I don't know who reads this, but I hope that this constructive suggestion helps

Do you want inquotes?
http://labs.google.com/inquotes/

http://blogoscoped.com/quotefinder/ was a little app here that allowed you to paste a text, and then highlighted those sentence which had a lot of phrase matches in Google... indicatin that the sentence might have been copied from elsewhere. The tool is Google SOAP API based, so ever since Google cancelled the SOAP API it stopped working, and I didn't update it yet (to work on e.g. Google's REST API)...