I don’t think the news about AOL buying Mailblocks and its challenge response anti-spam product is such a big deal in the grand scheme of things. But it does give me a quick opportunity to rant against challenge/response.
First, I don’t think the world is in danger of mass adoption of challenge/response. Earthlink, which in general has much more sophisticated customers than does AOL, has had a hard time gettings its adoption level of this up to the 7-10% level over a period of at least two years. I think it will be even tougher for AOL. I applaud AOL for trying to do more to help members fight spam, but I don’t think this is the answer.
So onto the rant. Challenge/response is a pretty poor solution to spam. Or, rather, I should say it’s an excellent solution to spam with humongous side effects. Some are documented in Pamela Parker’s article in ClickZ about this, but my top three issues are:
1. Challenge/response effectively eliminates everything other than personal email from people who like you. In other words, no emails from people like Fred who don’t have time to respond or work offline, no newsletters, no Wall Street Journal email alerts, no Amazon shipping confirmations, no eBay bid responses.
2. The flip side of the previous point is that for publishers and marketers, challenge/response is a nightmare. Manually responding to dozens of emails is hard enough — that is, if the marketer/publisher can find them and respond to them before they “expire.” But when the volume gets into the hundreds or thousands, it becomes a nightmare cost of being a non-spammer.
3. My final pet peeve? David Daniels nailed it in his quote in Pamela’s article — it solves the problem of too much email by tripling the volume of email (one email, one challenge, one response)!
Overall, it’s a crude solution to the problem, and one that I think will be obviated over time.