Digital Inspiration gives some recommendations on what to do when your work has been plagiarized.
One of the many steps is to convince their web host that the content is your:
What should I write in my complaint letter to the web host?
This is the toughest part – Your job is now to convince another person that you are the original owner of a particular content. Hence, you must submit as many proofs as possible to prove that you actually own the content. Here are some useful pointers:
» Provide a link of the Google Cache to prove that Google spiders discovered your content earlier.
» If you are site is mentioned in the Web archives (archives.org), share that information with the web host.
» Inform them about the Google Page Rank of your site – a site which indulges in copyright violations is generally a new site with no or a low pagerank.
» Share you Technorati Rank to prove that you are a popular blogger and thousands of sites are linking to your content. That may put the ball in your court.
» Share your Alexa Ranking and Traffic details to confirm the age of your site.
» Send the Google search results for link:labnol.blogspot.com to prove how may sites are actually linking to you.
There are just some example which should be sufficient to convince the web host. If the web host fails to act, move on the next step.
Good info I hope I never have to use. (Found via LifeHacker.)