Back in 2009, we published a post called "New Logical Captcha Plugins for WordPress". One of those plugins is no longer available. Since 2009 there have been many articles and discussions about using CAPTCHA and new plugins developed for preventing spam. Those maintaining websites need to prevent damage to their sites due to unwanted spam, yet these prevention methods often keep out legitimate site visitors, too.
We collected a list of a few articles and discussions about the issues with CAPTCHA. If you have slapped a CAPTCHA solution onto your site without considering what problems you might be causing legitimate visitors, you really need to take some time to read and learn from these articles. Note that many of them include even more links about the challenges. Kudos to the people working to resolve this long-standing problem with security solutions blocking legitimate visitors. There is still lots of work to do, so please consider sharing your knowledge or experience in the comments.
Articles and Discussions
- "Captcha Alternatives and thoughts – W3C", posted 15 Dec 2015.
- "reCAPTCHA Accessibility reVISTED by Terrill Thompson", posted 13 Dec 2015.
- "1.1.1 CAPTCHA", from the new Section 508.gov
- "The accessibility of Google’s No CAPTCHA" written by Derek Featherstone, posted 4 Dec 2014 in "Design, Understanding accessibility" [Article is no longer available as of May 2023.]
- "Google's No Captcha Shows Some Progress" from Web Axe, posted 7 Dec 2014.
- "Think Your Site Needs CAPTCHA? Try These User-Friendly Alternatives" from UserTesting Blog by Hannah Alvarez, posted April 9, 2014 – Updated 2 Dec 2014.
- "Effective alternatives to inaccessible CAPTCHAs" from VisionAustralia by Gerry Neustatl, posted 9 Dec 2014
- "Can CAPTCHAs Be Made Accessible?" from the American Foundation for the Blind, posted 21 Aug 2014.
- "Strict Standards: CAPTCHA Accessibility Criteria and Web Standards Compliance" from the BotDetect CAPTCHA site by Matej Saric, posted October 2013.
Here is a list of some plugins that claim to be accessible or user-friendly. Based on some of the discussions in the previous list, none of them are perfect solutions. Some claim to avoid issues for one disability, yet they still have issues for other disabilities. For example, do the logic-based tests consider issues with cognitive or learning disabilities? Let us know what you are using these days and why. [Someone once suggested an accessible slider as part of a CAPTCHA solution, but we couldn’t find that link. Please share it in the comments if you know what happened to that project.]
- AccessPress Anonymous Post by Access Keys
- Anti-Spam by CleanTalk – No Captcha, no comments and registrations spam
- Bot Block Stop Spam Referrals in Google Analytics
- BotScout Comment Protection
- Contact Form 7 Honeypot by Ryan
- Math Captcha by dFactory
- SI CAPTCHA Anti-Spam by Mike Challis
- Stop Spammers Spam Prevention by Keith Graham, plus free addons
- Check system.multicall Stop Spammer Addon
- Red Herring Stop Spammer Addon
- Wordfence Security plus get Wordfence Assistant to help Wordfence with some database enhancements.