There Are Three Big Website That Do This Free Of Cost
And Many More………..
Plagium is identified as one of the best alternative to the already established CopyScape to identify duplicate or copied content on the internet. This is a complete free service, however you could choose to donate them any money at your will.
DustBall Plagiarism Checker
DustBall is a simple Plagiarism checker that allows you to simply cut and paste a section of your webpage and hit the go button to identify the similar or duplicate content of the section on the internet.
PD is a very promising tool that worked great for me when I tested it out. Even though detection is free, they offer additional services at a price. The unique feature that I observed at PD is that they have a downloadable plug-in for Microsoft Word that could be very handy while writing article.
DupliChecker is a great tool that is also quite widely used by webmasters to identify plagiarism on the internet websites. This website allows you to even upload content to be checked and the service is totally free.
DupeFreePro is a very good paid alternative for the CopyScape to identified duplicate content on the Internet. One specialty of this application is that it is downloadable client software that works pretty very well. DFP also has a good support team.