Do You See What I See?
Watching Esther Williams tread water in those old 1940s movies is a cozy way to pass a rainy afternoon. But trying to decipher a computer screen with similarly swirling syllables is nobody's idea of a swank soiree. An audio CAPTCHA, on the other hand, is an attractive alternative to its visual counterpart.
Some people may be sufficiently turned off at the thought of navigating yet another visual CAPTCHA that they turn away from your site. Providing an alternative that may be easier for some people to navigate may prove an incentive for more people to unlock the virtual door to your site feedback.
Another reason for considering alternatives to visual CAPTCHA mechanisms involves a government regulation called "Section 508," officially known as "The Federal Electronic and Information Technology Accessibility and Compliance Act."
Section 508 (www.section508.gov) says that when Federal agencies develop or use electronic information, they are required to make that information available to everyone equally. In the case of CAPTCHA, this means that people who are unable to read a CAPTCHA should have access to an alternate entry mechanism. At least, that's my translation of the regulation's government-ese.
To date, Section 508 requirements apply only to sites with financial ties to the federal government. However, it makes good sense, from a business as well as a human standpoint, to provide accessibility alternatives for people with different physical challenges. Think about implementing these alternatives on your personal website as well as the business sites you develop.