WebAIM - Web Accessibility In Mind

E-mail List Archives

Re: Accessible captchas?

for

From: Stephan Wehner
Date: Dec 4, 2008 8:25AM


On Wed, Dec 3, 2008 at 12:14 PM, Jared Smith < <EMAIL REMOVED> > wrote:
> On Wed, Dec 3, 2008 at 1:04 PM, Peter Krantz < <EMAIL REMOVED> > wrote:
>> Are you sure you need a captcha? Is it possible to instead use a
>> server-side service (like Akismet) to deal with spam?
>
> Of maybe some of the approaches I outlined here -
> http://www.webaim.org/blog/spam_free_accessible_forms/

Those suggestions seem to be suitable against a generic
form-spam-robot "one-size-fits-all".
However, the approaches look pretty easy to overcome on a site-by-site basis:

Quoting from http://www.webaim.org/blog/spam_free_accessible_forms

"The techniques are:

* Detect spam-like content within submitted form elements
* Detect content within a hidden form element
* Validate the submitted form values
* Search for the same content in multiple form elements
* Generate dynamic content to ensure the form is submitted within
a specific time window or by the same user
* Create a multi-stage form or form verification page
* Ensure the form is posted from your server"


Stephan

> Stopping spam is a pretty marginal reason for burdening all of your
> users with a CAPTCHA. Implementing just a few of these techniques will
> stop 99%+ of spam without affecting the usability of the page at all.
> Those human spammers still get through, but CAPTCHA won't stop them
> either.
>
> Jared Smith
> WebAIM
>