The text "CAPTCHA Hall of Shame" warped, blended over a colored texture background, with black lines drawn over it

CAPTCHA Hall of Shame

by Critical Hippo


The problem

Advertisers who lack scruples have been deploying "spam bots," or automated processes that search for guestbooks, blogs, web forums, wikis, and other web sites that publish content written by the public, and send advertising messages to them. Some administrators of guestbooks, web forums, and the like have installed a visual CAPTCHA system to prevent automated processes from sending spam. This works by generating an image containing distorted glyphs of random characters, requiring the user to read the characters out of the image and enter them into a text field, and then when processing the form, making sure that the characters match the characters used to generate the image. Unfortunately, users behind a text terminal, such as visually impaired users who use a screen reader or refreshable braille display have no way of reading the image, no way of answering correctly, and no way of sending a message. Excluding visually impaired users in this way will likely run afoul of anti-discrimination laws in several countries, such as the Rehabilitation Act in the United States or the Disability Discrimination Act in the United Kingdom. For more information, please see "Further reading" below.

Sites made completely inaccessible by CAPTCHA

These provide no way for a person with a disability to contact the administrator in order to negotiate an alternative way of proving the person's good intentions, or they make blind users' access significantly more expensive.

Confusing examples

These sites provide a way for a visually impaired person to contact an administrator, but only determined users are likely to find it.

Good examples

These sites have recognized the inherent inaccessibility of a visual test and made an effort to present a straightforward way for inconvenienced users to contact the administrator, such as an e-mail address or a link to a web form.

Further reading

Opposing viewpoints

Contact the author

You may contact this Critical Hippo through e-mail at criticalhippo at pineight dot com