It has been over a week since the takedown of an ISP responsible for directing a large portion of Internet's spam. While many groups immediately hailed a massive drop in spam, the true story was more nuanced. Everyone, save the spammers, hates spam, and this story has generated quite a bit of interest throughout the media as a result. There are two misconceptions that do need to be clarified. The ISP did not directly send out somewhere north of one half of all spam on the Internet, but merely coordinated systems that sent the spam. If it sent out that much mail, it would be one of the largest traffic sources on the planet, and would have gone under from the bandwidth bills long ago. The ISP was responsible for directing systems to perform half of all spam sending attempts on the Internet, and was not responsible for half of all spam delivered to the inbox. ISPs that had strong content filters and multiple layers of IP blacklists saw a minimal change in the amount of spam delivered to their customer's inbox. The spam sent by this ISP was just not getting past the people who invested in good anti-spam protection.
I do think that the ISP shutdown is a landmark event as people will be emboldened to take down additional institutional supporters of spam when they see that removing hard infrastructure actually does have an effect. I hope it emboldens them to take what I believe is the next necessary step in the offensive war on spam: the financial infrastructure. If you truly want to hurt the spammers, find a way of freeing the world of the credit card processors that process the spammers' transactions. This may possibly raise the financial cost for certain kinds of spam to make it unprofitable and remove it from the net.
One can only hope.