Peter

<p>Stop a lot of spambots from polluting your site by making visitors identify a random word displayed as an image before commenting and optionally before registering. You can customize the pool of words to display.</p>
<h4>Features</h4>
<ul>
<li>
<p>Toggle whether registered users need to enter the word</p>
</li>
<li>
<p>Random font display</p>
</li>
<li>
<p>No cookies required</p>
</li>
<li>
<p>No JavaScript required</p>
</li>
<li>
<p>Auto-generated audio for visually impaired users</p>
</li>
<li>
<p>Easy-to-read</p>
</li>
<li>
<p>No mapping of words from the code — words are used once or removed after 24 hours</p>
</li>
<li>
<p>Reminder of what was entered if you get the word wrong</p>
</li>
<li>
<p>Selective blocking of trackbacks, pingbacks</p>
</li>
<li>
<p>Easy to translate</p>
</li>
<li>
<p>Compatible with caching plugins</p>
</li>
</ul>
<h4>Negatives</h4>
<ul>
<li>
<p>Purposely no obscuring techniques so that the anti-spam word is easy to read</p>
</li>
<li>
<p>The more people who use this plugin, the more motivation for spambots to target it</p>
</li>
</ul>
<h4>Requirements</h4>
<ul>
<li>
<p>GD Library and FreeType Library (There’s a diagnostic page to tell you whether you have them installed. If needed, just ask your web host to install them!)</p>
</li>
<li>
<p>WordPress 3.2 or higher</p>
</li>
</ul>
<h4>Translations</h4>
<ul>
<li>ru_RU translation by koc</li>
<li>sk_SK translation by Patrik Žec (PATWIST) of http://patwist.com</li>
</ul>


Peter’s Custom Anti-Spam

Stop a lot of spambots from polluting your site by making visitors identify a custom word displayed as an image before commenting.

<p>yaCAPTCHA is a CAPTCHA plugin for WordPress that helps you block comment spam<br />
from automated bots. In order to post comments, users will have to write down<br />
the characters that are part of an image. Since it is relatively hard for<br />
automated programs to figure out those characters, this will help prevent<br />
comment spam from those programs.</p>
<h4>Requirements</h4>
<ul>
<li>WordPress 1.5 or higher.</li>
<li>PHP 4.1.0 or higher with GD2 library support.</li>
<li>Theme must support the ‘comment_form’ action.</li>
<li>PHP sessions enabled and properly configured.</li>
</ul>
<p>In case you are wondering, most hosting providers should have those basic<br />
requirements in place.</p>
<h4>Strengths vs other solutions</h4>
<ul>
<li>Easy to install</li>
<li>Does not require Javascript to work</li>
<li>Broad WordPress version support</li>
</ul>
<h3>Thanks</h3>
<p>Thanks to Kruglov Sergei for creating KCAPTCHA, his pretty good CAPTCHA. You<br />
can visit KCAPTCHA website <a href="http://www.captcha.ru/en/kcaptcha/" title="KCAPTCHA
website">here</a>.</p>


yaCAPTCHA

yaCAPTCHA is a CAPTCHA plugin for WordPress that helps you block comment spam from automated bots.

Peter’s Custom Anti-Spam vs yaCAPTCHA