Yahoo is now using audio anti-bot verification codes

http://arc.help.yahoo.com/arc/arc.php now gives you anti-bot verification options for Text or Audio codes

Text code

If you are having trouble seeing this image, that's normal! The text is intentionally distorted to help fight automated spam programs. If no image appears, please make sure your browser is set to display images and try again.

If you are not sure what the code is, make your best guess. If you guess incorrectly, you can try a different code on the next screen after you submit the form. Codes may contain a mixture of letters and numbers, and letters are not case sensitive.

Audio code

You can also try an audio code instead by clicking on "Play the audio code". Your cursor will automatically move to the text entry box, and you will hear a prompt followed by a series of numbers with background noise. Type the numbers you hear into the text box instead of the code in the image.