Evan Solomon

When you click links, your browser sends referrer information to the site you land on. This is how you get things like referrer counts in Google Analytics. Sometimes, though, you don’t want people to know where you clicked their links from. By default, this plugin will hide your referrers for links from <code>wp-admin</code>. You can also use it to hide links on the front end of your site by making a plugin along the lines of this.
<pre><code>add_action( 'wp_enqueue_scripts', 'es_anonymous_admin_links' ); </code></pre>

Anonymous Admin Links

Hide the referrer for external links in wp-admin using href.li

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".

Anonymous Admin Links vs track-incoming-referrer