title: What does header('P3P: CP="CAO PSA OUR"'); do?
body: <p>What is <code>header('P3P: CP="CAO PSA OUR"');</code> for?</p>
  
  <p>How/why will it let this script work fine in IE?</p>
  
  <pre><code>session_start();
  
  if (!session_is_registered(pre_myusername)) {
      header("location:index.php");
      exit();
  }
  </code></pre>