For OCT-2010, the number is pretty standard and similar to previous months. Out of those top 1 million sites, around 3.6 thousand got blacklisted last month (3,683 to be more exact). Out of the top 100k, more than 408 got blacklisted by Google.
Over time, only 711 sites that were blacklisted in previous months are still blacklisted and in their TOP 1 million ranking.
Those are the top 100 sites that got flagged and their respective ranking (You can get the full list here):
One interesting point is that more than 70% of the legitimate sites that got hacked were using outdated software (either Joomla, WordPress, OpenX, etc). If you are a site owner, this is a reminder to keep your site updated.
We will post more details in future posts. If you have any question or comment about it, let us know.