title: What does fb: namespace stand for?
body: <p>It might a bug in documentation or just me getting it wrong, but in any case I think it is confusing to see several different definitions of the same fb: namespace:</p>
  
  <ul>
  <li><code>xmlns:fb="http://www.facebook.com/2008/fbml"</code>
  <br>Given as example <a href="http://developers.facebook.com/docs/opengraph/" rel="nofollow noreferrer">here</a>.</li>
  <li><code>xmlns:fb="http://ogp.me/ns/fb#"</code>
  <br>Shows up in the generated XFBML code <a href="http://developers.facebook.com/docs/reference/plugins/like/" rel="nofollow noreferrer">here</a>.</li>
  </ul>
  
  <p>So which one should the developers use?</p>