alexmoskovsky

Provided by <a href="http://multitoolbox.com/" rel="nofollow ugc">Multitoolbox</a>.
Simple, but strong captcha, built to prevent spam in WordPress comments. Succesfully blocks Xrumer-like tools.
To leave a comment on your blog, visitors need to simple check the captcha’s field. That’s all! Forget about annoying typeing of letters and digits.
Features:
<ul>
<li>Extremely simple passing for human;</li>
<li>Built-in id’s and function name’s generator to produce unique and random values, Xrumer won’t pass;</li>
<li>Catchy look, you commentators won’t miss;</li>
<li>Captcha’s code will be pasted into the comment form via JavaScript, so spam-bots will get a big parsing problems; </li>
<li>Comment text saving, so if commentators forgot to check captcha’s field, they never have to write commen again.</li>
</ul>
Languages:
<ul>
<li>English;</li>
<li>Русский;</li>
<li>Український (thanks to <a href="http://sweatego.ru/" rel="nofollow ugc">Sweat Tony</a>);</li>
<li>Italiano (thanks to <a href="http://sweatego.ru/" rel="nofollow ugc">Sweat Tony</a>).</li>
<li>Čeština (thanks to <a href="http://spa-ostrov.ru/" rel="nofollow ugc">Zeleny Rajce</a>).</li>
<li>Français (thanks to <a href="http://www.android-software.fr/" rel="nofollow ugc">Laurent</a>).</li>
<li>Беларуская (thanks to <a href="http://pc.de/" rel="nofollow ugc">Marcis G.</a>).</li>
</ul>
Amcaptcha is bulletproof solution tested on many blogs.

Amcaptcha

Simple, but strong captcha, built to prevent spam in Wordpress comments. One-click solution tested on many blogs!

convatic

Convatic is a revolutionary social commenting system for websites. This plugin overlays and plays nicely with themes and other plugins. The idea behind Convatic is freedom. Freedom builds communities. Convatic promotes and engages visitors turning websites into vibrant communities.
<ul>
<li>Store comments within your website and completely own them.</li>
<li>Use Akismet for spam protection.</li>
<li>Commenter ratings – Users can up and down vote comments affecting commenter rating across the Convatic network of sites. This promotes good commenting and helps your visitors decipher bad comments.</li>
<li>Signup freedom – Commenters create profiles across the Convatic community by simply writing a comment. Registration and commenting are combined to streamline conversations. Commenters have the option to password protect their email. Password protection is optional since most people just want to comment.</li>
<li>Allow commenters to subscribe to email notifications for comment threads</li>
</ul>

Convatic

Convatic is a revolutionary social commenting system for websites. This plugin overlays and plays nicely with themes and other plugins.

Amcaptcha vs Convatic