Take eg JAYS-XXX-LINKS.COM:
http://www.google.com/search?q=allin...n&lr=&c2coff=1
http://reality-xxx-adult-porn.info/
has almost an identical site to jay's as a cloaked version he just changed jay's into Juan's but if you surf the site as googlebot you will be astonished.
i dont know why some sites get knocked down, it hit me the first time a few days ago. maybe because jay's site is older it can withstand that dup. filter, but maybe it is luck and jay will be gone from google next time.
btw. this is the same guy who copied my site so dont bother and show jay this post, i already complained and reported the entire network of that guy (which took me all night) but if jay starts compaining it will help, too.
... and check your site.