Amanda &amp; Steve

Is this the ultimate in automated ‘bot Spam Killers?
Spam is the bane of WordPress admin’s lives; auto-generated Spam can bypass unset hidden fields from the WordPress comment page by directly submitting the comment to WordPress.
This plugin does two things:
<ul>
<li>Removes the ‘Comment Author URL’ field from the WordPress comments form; for most non-technical blogs this optional field is irrelevant.</li>
<li>Kills WP (hey that saves some CPU cycles) if a comment is submitted which contains a Comment Author URL.</li>
</ul>
Website spam ‘bots have two aims, firstly they populate spam links within the main body of a spam comment, and the spam ‘bot also includes the spam destination in the Comment Author URL of the comment field.
We put together this little plugin as despite running two other anti-spam plugins + Google Captcha, ‘bot spam was still getting through. This was resulting in an hour or so each week weeding out the real comments that had fallen into the spam bucket due to the real commenter failing to complete the Google Captcha correctly. We also noticed that real user comments reduced with Google Captcha in place.
We don’t need to stand for this any longer; say goodbye to Comment Author URL Spam and save CPU cycles!

TMD Spam Killer

Hides the 'Comment Website URL' field, kills WP if a spam 'bot submits a comment which includes a Comment Author URL.

Milan Dinić

Ryan Hellyer

Bjørn Johansen

Brian Layman

Stops automated spam while remaining as unobtrusive as possible to regular commenters. <a href="https://geek.hellyer.kiwi/products/spam-destroyer/" rel="nofollow ugc">The Spam Destroyer plugin</a> is intended to be effortless to use. Simply install, and enjoy a spam free website 🙂
<h3>Credits</h3>
<ul>
<li><a href="https://wordpress.org/support/users/omahoung/" rel="ugc">omahoung</a> – Bug reporting</li>
<li><a href="https://wordpress.org/support/profile/stromhalm" rel="ugc">Stromhalm</a> – Bug reporting</li>
<li><a href="http://ocaoimh.ie/" rel="nofollow ugc">Donncha O Caoimh</a> – Developer of Cookies for Comments, functionality of which is incorporated into Spam Destroyer</li>
<li><a href="http://elliottback.com/" rel="nofollow ugc">Elliot Back</a> – Developer of WP Hashcash, functionality of which is incorporated into Spam Destroyer</li>
<li><a href="http://nettsett.no/" rel="nofollow ugc">Marte Sollund and Ingvild Evje</a> – Bug reporting</li>
<li><a href="http://eHermitsInc.com/" rel="nofollow ugc">Brian Layman</a> – Code advice</li>
<li><a href="http://ronalfy.com/" rel="nofollow ugc">Ronald Huereca</a> – JS advice</li>
<li><a href="https://twitter.com/shawngaffney" rel="nofollow ugc">Shawn Gaffney</a> – Bug reporting</li>
<li><a href="http://konstruktors.com/" rel="nofollow ugc">Kaspars Dambis</a> – Bug reporting</li>
<li><a href="http://www.wanderingjon.com/" rel="nofollow ugc">Jon Brown</a> – Added error message filter</li>
</ul>

Spam Destroyer

Kills spam dead in it's tracks. Be gone evil demon spam!

TMD Spam Killer vs Spam Destroyer