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CAPTCHA State of the Union 2005

Filed in: accessibility, design, Web, Fri, Jan 28 2005 12:21 PT

I have to say, this week is really going well. On Monday, Eric Meyer (whom you may know for having more CSS knowledge in his pinky toe than most of us have in our entire bodies) released a WordPress anti-spam plugin that uses logic puzzles. This is another good thing that has maybe sort of indirectly resulted from the anti-CAPTCHA paper I wrote a year and change ago: logic tests were among the alternatives suggested.

I’ve also seen recent evidence of email providers watching the patterns of new users (if not the actual content) for conduct consistent with a spammer, along with limited-use accounts for new users, which could cut down on at least the simplest spammers’ reach. Both of those were in the paper, too.

There are a few things I want to note here. First is that the big companies that got hooked on the idea of CAPTCHA as panacea are no longer so keen. The visual CAPTCHAs are still problematic for accessibility, and will be so long as they’re limited to people with good vision (and without dyslexia).

The only places where early CAPTCHA implementations are on the rise are blogs and small sites who think they’re doing the right thing, perhaps because they saw the big guys doing it first. That wave has crested and receded, and it’s time to learn from the problems they had. Bloggers, in particular, have an ever-increasing arsenal of useful tools, including Bayesian filtering, that can kill off comment and trackback spam pretty effectively. There is still more to be learned here, but the message is that there are better, more inclusive means of solving your problems. (Side note: “but blind people don’t read my blog!” is the weakest excuse ever. If doesn’t work for people who don’t want to install wheelchair ramps in their office buildings, it sure doesn’t work for you.)

The second thing I want to say is that the CAPTCHA developers (and there are actually several groups working on CAPTCHA-like systems) are not evil ogres bent on the destruction of the Web’s utility to users with disabilities. A number of them have contacted me in recent times to tell me about projects they’re working on, and they range from allowing a choice of visual or audio cues, which is at least an improvement, to adding logic tests and other approaches cited in the paper. The good news is that the message has gotten through, and we can all work together. After all, it’s nothing a screaming mob with pitchforks and torches can’t solve, right?

(I still maintain that “Inaccessibility of Visually-Oriented Anti-Robot Tests: Problems and Alternatives” is not as fun a name as its original title: “On the Internet, Nobody Knows You’re a Robot”.)

4 responses to “CAPTCHA State of the Union 2005”

  1. Eric Meyer says:

    For the record, I don’t think I ever saw your paper (whose original title is indeed MUCH better); or if I did, I’d long since forgotten. I think is likely to be a case of an idea being so good that multiple people arrived at it. You just got there well ahead of the rest of us!

    In my case, I wanted a spam barrier that was accessible and didn’t require JavaScript. I was saying so to Photo Matt and he suggested I use “What is Eric’s first name?”, pointing out that a similar approach was working very well for Jeremy Zawodny. I, of course, immediately took that simple, basic idea and dramatically over-engineered it. I mean, really, what else would one do in such a situation?

  2. Pete says:

    Your original paper was the inspiration for me to create a proposal (and some code) for an accessible captcha. As you mention in your paper logic puzzles have two drawbacks: (a) they require someone to write a library of them and (b) they may be difficult for users from a different culture.

    My suggestion is to refrain from captchas if possible. Search engines are already ignoring comment spam if you use the proper markup.

  3. jon says:

    when you say “logic puzzles” it makes it sound like only a few would *ever* get a comment in. 🙂 when i see “what is eric’s first name”, then i’m a bit more relieved.


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