Show content only for organic traffic
<p>I want to show some content only for visitors from search engines,
can you help me please ? :)</p>

<p>I already have this php, but it show only for google.com but I want whole google and yahoo :)</p>

<pre><code>if(substr((trim($_SERVER['HTTP_REFERER'])), 0, 23) == "http://www.google.com/")
{
    echo "Show what I want";
}
</code></pre>
