I read with some amusement the pledge to end spam within 2 years that Microsoft Chairman and Chief Software Architect Bill Gates made during his annual visit to the World Economic Forum in Davos, Switzerland. I was amused because I woke up this morning, as I did yesterday, to dozens of spam messages, all of which had somehow made it past the cunningly created and continually updated server-side spam filters I erected on my mail server. Spam is like water poking away endlessly at a concrete barrier: No matter how well you build that wall, no matter how strong it's fortified, it's eventually going to give way to the water. And, like a force of nature, spam is seemingly invincible--oblivious to the blocks I put in its way. Every day I spend a lot of time--too much time--dealing with this plague.
   So, how will Gates end spam? We already know that Microsoft has created spam-filtering technologies for use in its Microsoft Exchange Server, Microsoft Outlook, and MSN Hotmail products. And last year, the company began working with state and federal governments to pursue the most virulent spammers, putting a less technological and more lawful face on the battle against spam. But recent legal moves in the United States will have little effect on most American spammers. Worldwide, spammers can set up virtual shops anywhere to bypass local laws; it happens every day.
   These technological and legal efforts have been largely unsuccessful if you measure success by whether they prevent spam from reaching end users. Many of you have probably experienced the pain of setting up a spam filter with a rating that's too high, causing important email messages to be blocked. But when you set it to a lower setting, you end up having to manually delete the email messages you don't want. Although we'll always be able to improve the fairly impressive results we get with the Bayesian-type spam filtering that most spam filters now use, such filters will never be a cure-all. I'm glad my spam filter caught 218 spam messages this morning (I checked); I'm not so happy that it let more than 50 spam messages through.
   Gates says that Microsoft is looking at several solutions, some of which are further along than others. One obvious solution is a challenge-response system, which Mailblocks and other innovative email services use. This system forces first-time emailers to respond to an email query before their messages are delivered to you, ensuring that they're human. If Microsoft were to adopt such a system--perhaps by purchasing Mailblocks--and use the system in its market-leading Hotmail service, the company could almost instantly stem the tide of much of the spam that's delivered worldwide. But other popular email providers, such as Yahoo!, would need to adopt similar systems for this approach to be globally successful.
   Another possible approach, Gates says, is an email payment system in which users can charge fees for email messages they receive. If the fee is too high, the theory goes, spammers and other bulk mailers won't bother sending email to users. This approach is interesting but is the least well defined, Gates admitted.
   One solution that Gates didn't mention that could be the most effective is a complete overhaul of the poorly designed email infrastructure. Right now, email users can pose as other users or obfuscate their identities and relay mail through remote hosts, making it next to impossible for authorities or angered email recipients to track them down. No company or organization is moving too quickly toward a reformation of the system, however, largely because of the pain and cost it would incur. Email has become a crucial business and social tool, and the email infrastructure we all use is clearly broken. I wonder which kind of catastrophe will have to happen before we take the necessary steps to fix this disastrous bit of technology that we rely on so heavily each day.
   In the meantime, I'll continue to wade through email I never should have received--email that advertises "V1@GRA," online football betting, auto loans, and possible financial relationships with suspicious people from Eastern Europe and Nigeria. Can't we put a stop to this silliness?