http://www.phpbb.com/about/features/compare.php

On the phpBB comparison page it says that if there are any errors to report them to the website bug tracker.

In the Anti-Spam category, the CAPTCHA Visual Confirmation comparison for SMF is not entirely correct. SMF does not have visual verification (CAPTCHA) for guest posting.

In actuality, SMF's CAPTCHA support is not full, it is partial. Showing YES in that field leads one to believe that SMF has full CAPTCHA support when it does not.