At A List Apart, the article Graceful E-Mail Obfuscation makes me think about a funny aspect of the spam war. There's a neverending march of articles with the latest and greatest method for defeating spam in its many pernicious forms. Individuals have long used their own favorite method of obfuscating their addresses when posting them in public places (although it seems more common today to simply hide them entirely and use safer methods of communication, such as private messages on message boards). Spam and email address harvesting are volume businesses, so it's true that even if your address is easily parsed by a human, a harvester (the person) would never bother with manually searching it out, and they probably won't bother trying to make their harvesting programs smart enough to parse every possible obfuscation. But if a particular method, such as replacing @ with (a), becomes popular enough, it might become worthwhile for the harvester to gain a competitive advantage by enabling their program to parse it. The same is true for many other cases, such as spam filters in email programs.

So in a sense, the best way to ensure the defeat of an anti-spam method is to popularize it. The only way to win the war is for everyone to have their own custom anti-spam measures, such that there's no efficient way for a spammer to outwit all of them. On some level people already do this--they obfuscate their email addresses in their own funny little way, and lots of people who run web sites come up with their own little system or clever CAPTCHA. In other cases, such as email filtering, it's far less practical for individuals to take the time to do this. This is a problem that resists the incredible efficiency of distributing software--people writing programs or plugins or writing articles with some html code are doomed to be defeated by their own success, while anyone creative, self-motivating, and perhaps selfish enough can win.