How do I hide certain elements on my page, based on referral traffic?
<p>More specifically, how do I hide ads? I pose this question after reading this:
<a href="http://www.codinghorror.com/blog/2007/06/how-to-advertise-on-your-blog-without-completely-selling-out.html" rel="nofollow">coding horror entry</a></p>

<p>In it, he states</p>

<blockquote>
  <p>As a courtesy, turn off ads for Digg, Reddit, and other popular
  referring URLs. This audience doesn't appreciate ads, and they're the
  least likely to click them anyway.</p>
</blockquote>

<p>I agree with what he says. So how do I do this?</p>
