averageradical

Non-technical summary: Track incoming referrer and write it to any hidden form field with the identifier “referrer” (this can be created in Contact Form 7, for example; see below). Also if the WordPress site redirects from HTTP to HTTPS, this plugin also overrides the redirect to add the referrer to the https URL.
Technical details: This plugin runs client-side JavaScript in every page in HEAD and if there isn’t a session cookie with the name “referrer”, then it writes a session cookie with the name “referrer” and the value of either document.referrer, or if that’s empty, the URL-encoded value of window.location.href. There is another client-side JavaScript in every page before which writes the value of the “referrer” cookie to any INPUT with the ID “referrer”, if it exists.
When integrating with Contact Form 7, add a hidden input field such as the following:
<pre><code>[hidden referrer id:referrer]
</code></pre>
And then add to the Mail’s Message Body:
<pre><code>Referrer: [referrer]
</code></pre>
If you’re just integrating this with HTML, just add this to any form:
<pre><code><input type="hidden" id="referrer" name="referrer" />
</code></pre>

track-incoming-referrer

Track incoming referrer and write it to any hidden form field with the identifier "referrer".

Denis Buka

Creates navigation to next and previous posts specific to the category or tag a visitor came from. You can embed the navigation automatically or use a custom function <code>addIntNav()</code> in your template files. Customize the appearance with post thumbnails and labels. Swap next and previous post links mirror-wise. Bold links to the current category or tag. Optimized for use with caching plugins.
Features overview:
<ul>
<li>Add next/previous navigation links to your post specific to the category or tag a visitor came from. </li>
<li>Optionally highlight referrer link occurrances on page. </li>
<li>Insert navigation automatically above or below post content or use a custom function – <code>addIntNav()</code>. </li>
<li>Choose wheather navigation should contain labels and post thumbnails. </li>
<li>Swap next and previous links mirror-wise. </li>
<li>Optionally load navigation links in a frame if you’re using caching plugins on your site. </li>
</ul>
My other plugins:
<ul>
<li>Generate Cache (https://wordpress.org/extend/plugins/generate-cache/) </li>
<li>Drop in Dropbox (https://wordpress.org/extend/plugins/drop-in-dropbox/) </li>
</ul>
Links: <a href="http://steamingkettle.net" rel="nofollow ugc">Steaming Kettle Website Design & Video Production Studio</a>

Intuitive Navigation

Creates navigation to next and previous posts based on the category or tag a visitor came from.

track-incoming-referrer vs Intuitive Navigation