In what might possibly be the largest websites ban ever in its history, Google has removed more than 11 million domains from its search result.
Google's decision to ban these websites is because of the huge number of spam and phishing websites hosted at this domain. According to a recent report from the Anti-Phishing Working Group, the .co.cc domain hosts around 5000 phishing websites.
Although the TLD .cc is officially owned by the Cocos (Keeling) Islands, the domain .co.cc is not an officially recognized second level domain. The domain http://co.cc/ is owned by a Korean company and they are the one providing the 11 million .co.cc sub domains.
According to Matt Cutts from the Google Spam Team, Google classifies .co.cc as a free host and so they have the right to take action on .co.cc as a whole.
First, a definition: a "freehost" is a domain that will let anyone register a site on that domain. There's lots and lots of high-quality freehosts out there (wordpress.com comes to mind).
We absolutely do try to be granular, but I wanted to mention that if we see a very large fraction of sites on a specific freehost be spammy or low-quality, we do reserve the right to take action on the freehost as a whole. I think most savvy search/SEO folks would understand this completely, but I figure it's better to over-communicate than under-communicate.
via: The Register