LiveJournal has one (scroll to the bottom of the page). It's open source.

(The implication being, of course, not that it is "free" to implement audio captcha, but that it is not impossible; that a site with millions of users has chosen to do so; and that they share the way they did it with other potential programmers.)

In reply to Re^5: Stop Form Hurling by gaal
in thread Stop Form Hurling by awohld

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


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