Forget about Copyscape, here's a 100% free article uniqueness checker that I've never heard anyone on here mention. It's a fast, simple app that runs from your desktop--works on Windows, Linux, and Mac. This tool is offered by TextBroker for its writers, so they can check for duplicate content before submitting their articles. I've been using it for a while and I've found it to be very useful. It's called Un.co.ver and you can get it here: http://www.textbroker.com/uncover/ If you like this, well... you know what to do.