title: what is the difference between <pubDate> and <dc:date> in feed's structure
body: <p>can any one please let me know the main difference between <code>&lt;pubDate&gt;</code> and <code>&lt;dc:date&gt;</code> in feed's structure. also please explain</p>
  
  <pre><code>&lt;dc:date&gt;
  &lt;dc:creator&gt;
  &lt;dc:....&gt;
  &lt;dc:....&gt;
  </code></pre>
  
  <p>will those be required for building feeds?</p>