title: What determines whether the 'Compatibility View' button appears in Internet Explorer 8 or not?
body: <p>On some sites I'm developing, I noticed that the 'Compatibility View' button is shown beside the address bar. Yet when I view other websites, this button is not always available to me.  </p>
  
  <p>What determines whether or not this button is shown to the user?  Does it have to do with the <code>&lt;meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7"&gt;</code> header tag?</p>
  
  <p>(Screenshot below of what I'm talking about)</p>
  
  <hr>
  
  <p><a href="http://img380.imageshack.us/img380/4858/compatabilitybutton.png" rel="nofollow noreferrer">alt text http://img380.imageshack.us/img380/4858/compatabilitybutton.png</a></p>