With the exponential rise in Blogger comment spam, a lot of folks have turned on comment verification, even though they know it makes it difficult for blind/low vision/dyslexic folks to post comments.
Roger Johansson provides an entry about the W3C’s analysis of the problems with CAPTCHA. Unfortunately the solutions are enterprise-oriented (individual bloggers, especially those using services like LiveJournal and Blogger, aren’t going to be able to implement them independently), but the more we understand the problem, the more we can urge the services we patronise to adopt an accessible solution to preventing comment spam.
You make a very valid point on this issue. We have been using a plugin called Spam Karma on two of the blogs I am involved with. Works great. Transparent to the visitor and nothing has sneaked by yet. I think we need to convince the blog farms that there are alternatives in spam trapping technology that will not impact on accessibility. This sounds like it is nothing more than a “reasonable accommodation” on their part???
Spam Karma is great, but it’s a WordPress solution. Movable Type users can go with MT-Blacklist (or 3.2’s builtin spam protection). But what’s the (perhaps technologically less sophisticated) Typepad, Blogger, LiveJournal, Dairyland, etc, user to do?
Filters like Spam Karma are always playing a game of catch-up. There are better accessible solutions available, such as a simple quiz (e.g. “What two plus two? Spell the answer out.”)