Over on the Google Enterprise blog there is summary of the 2008 spam year in review. Covering the trends as seen by the Postini Message Security network, which Google acquired in July of 2007.

A number of the provided graphs show surge in April of 2008 for the number of spam messages blocked followed by a significant drop is spam levels last November after McColo was taken off line. These graphs also show a disturbing yet steady recovery and continued increase in spam levels.

Most surprising are Google’s statistics on the quick recover and growth of spam after McColo was taken offline:

Spam threats rose visibly in 2008, reflecting the overall trend of rising attacks. Even with the drop in November 2008, spam levels climbed 25% over 2007. Our statistics show that the average unprotected user would have received 45,000 spam messages in 2008 (up from 36,000 in 2007). All indicators suggest this trend will continue as virus, malware, and link-based attacks become both more frequent and more ingenious.

At this rate 2009 will bring us 56,000 spam messages per user…