According to McAfee's monthly spam report:
McColo has taught botnet owners a lesson. As a result, botnet control centers have become more distributed, spanning many networks in many countries. The loss of a big hosting provider today would prove only a minor inconvenience – as opposed to a major defeat – for spammers.
As we reported on our IT Business Edge site, a recent MassageLabs report found that botnets dominated the cyber security landscape in 2009 with 10 major botnets controlling at least 5 million computers.