Google has dumped over 11 million websites, all of which are on the .co.cc domain name. The .co.cc TLS is not an officially authorised second-level domain (like .co.uk or .com.au) but is owned by a Korean company that has decided to offer it as a free domain option.

Google decided to remove the entire network of .co.cc domains because they are far too "spammy". Google said this is nothing more than a free host. "If we see a very large fraction of sites on a specific freehost are spammy or low-quality", according to Matt Cutts, head of Google's web spam team.

More info is available on the google blog: http://googleonlinesecurity.blogspot.com/2011/06/protecting-users-from-malware-hosted-on.html

And if you happen to have a few of those domains, might as well drop 'em!