Rhys Wynne

<p>This plugin quite simply lets you know where the users entered your site when they leave a comment. A lot of people who joined the do-follow movement are listed on sites which are a target for comment spammers. To those who suffer comment spam can now find out the page they come from, and block accordingly.</p>
<p>This plugin uses a cookie to track the commenter, so if the user hits the first page first, they will still be tracked.</p>


InComment

Adds an extra "referral" note to the bottom of comment forms, so you could see where people come from comment. Useful for finding resources  …

LukaszWiecek

<p>The “Smart DoFollow” plugins lets you automatically give DoFollow links to authors of comments that are longer than a given number of chars. You can reward the authors of long comments with strong links that have SEO-value.</p>
<h4>My other plugins</h4>
<ul>
<li><a href="https://wordpress.org/extend/plugins/social-slider/" title="Social Slider" rel="ugc">Social Slider</a></li>
<li><a href="https://wordpress.org/extend/plugins/socialfit/" title="Social Fit" rel="ugc">Social Fit</a></li>
<li><a href="http://commentify.info/" title="Commentify" rel="nofollow ugc">Commentify</a></li>
<li><a href="https://wordpress.org/extend/plugins/thank-you/" title="Thank You" rel="ugc">Thank You</a></li>
</ul>
<h4>Translations</h4>
<ul>
<li>English – <a href="http://tomasz.topa.pl" title="Tomasz Topa" rel="nofollow ugc">Tomasz Topa</a></li>
<li>Polish – <a href="http://mydiy.pl" title="Łukasz Więcek" rel="nofollow ugc">Łukasz Więcek</a></li>
</ul>


Smart DoFollow

The "Smart DoFollow" plugins lets you automatically give DoFollow links to authors of comments that are longer than a given number of chars.

InComment vs Smart DoFollow