Many people have reported great success when using this module to prevent spam bots and other forms of spam. Some of these people's stories are collected below, for those who wish to know:
I installed Honeypot yesterday and within a few minutes it was blocking 100% of my spam! It's like watching a zombie trying to walk through a wall, over and over again. :-)
I'd like to leave this open for everyone to share their success stories with Honeypot. The discussions here could even be added to a Testimonials section on the project page to help promote the module and its techniques.
Thanks for the validation of this project's efforts! I've experienced a huge reduction in new account spam on Flocknote, Midwestern Mac, and Open Source Catholic, three sites for which I originally developed this module.
Also, I hear it's working well on drupal.org (see: #1759272: Test honeypot module on http://drupal.org) and groups.drupal.org (see: #1833564: Deploy honeypot to cut down on bot registrations), if that's any help to someone evaluating the module :)