Just stumbled upon this today.Copyscape is a really cool tool, which scans through an archive that it has built from pages on the internet, and gives you a list of websites that closely resemble content on your website. I ran my blog through, and I found only pages, with some content resembling mine. I am not worried, because this was ‘quoted’ content anyway. Several blogs had ‘quoted’ from the famed feynman commencement lecture.
Check out http://www.copyscape.com
Interestingly it has a very google-sque appearance.