When I wrote a column in the Observer about spam I had a huge postbag (well, inbox) in response — more than I ever remember about any other subject. It felt as though I had touched a raw nerve. But I also had messages from readers claiming that I was going overboard — that spam was a nuisance, certainly, but a tolerable one. In vain have I tried to explain that, if unchecked, spam will lead to a tragedy of the digital commons which we will all one day rue. So I was pleased to see that someone else takes it seriously. “On Feb. 18 and 19”, this Business Week piece begins, “e-mail delivery to thousands of AT&T WorldNet customers slowed to a trickle. Some messages took as many as 24 hours to arrive — an eternity in Internet time. The reason? Spam — those irritating, unwanted e-mail messages that clog your in-box hawking everything from hot sex and Viagra to interest-free loans. WorldNet, which processes 15 million to 20 million messages each day, was suddenly besieged by millions of junk e-mail pitches — just as one of its sophisticated anti-spam filters went on the blink. It was the first time that spam brought a large Internet service provider (ISP) to a virtual standstill. “