This site checks websites for copyright infringement. It will show whether someone copied you or you vice versa - and it will show you when.
You enter a website name. Plfer checks it. If it finds any infringements, it lets you easily post the evidence to Facebook and Twitter.
Some results also allow you the option to take additional action, like issue DMCA removal notices or contact infringers.
Finally, we can prepare a detailed infringement report to take to your legal contacts if you want to escalate the matter.