This is the first trade publication I've seen that's covered some of the issues with ISPs blocking or not blocking ports.
Port blocking last resort in fight against virus Long term problems can be caused by port blocking by Paul Brislen and James Niccolai, Auckland and San Francisco http://computerworld.co.nz/webhome.nsf/UNID/BEC6DE12EC6AE16ECC256D8000192BF7!opendocument "While some end users are calling for ISPs to block certain ports relating to the Microsoft exploit as reported yesterday (Feared RPC worm starts to spread), most ISPs are reluctant to do so."
