McColo goes offline

Last week a major player in the botnet arena was taken offline when they were shutdown by their upstream provider.  With the demise of McColo, there has been a 30 – 50% drop in the amount of spam as measured by any number of different techniques. The CBL team has posted an article about their view of the McColo disconnection, which includes links to press articles about the shutdown. Spamhaus has their own take on the shutdown and another collection of links to articles about the shutdown.
In my own mailbox, I have noticed a drastic decrease in the amount of spam over the last week. I am too jaded to expect that the change is permanent, but it is nice while it lasts.