title: Clarification on the HTML5 pubdate attribute
body: <p>Can some one explain to me in layman's terms what the following sentences, from the <a href="http://dev.w3.org/html5/spec/Overview.html#attr-time-pubdate" rel="nofollow noreferrer">W3C specification working draft</a>, below mean about the <code>pubdate</code> attribute for the time element below.</p>
  
  <blockquote>
    <p>For each <code>article</code> element, there must be no more than one <code>time</code> element with a <code>pubdate</code> attribute whose nearest ancestor is that <code>article</code> element. Furthermore, for each Document, there must be no more than one time element with a <code>pubdate</code> attribute that does not have an ancestor <code>article</code> element.</p>
  </blockquote>