title: What does i:nil="true" mean?
body: <p>I have an xml and it has nodes with i:nil="true" in it.  What does that mean?</p>
  
  <p>For example:</p>
  
  <pre><code>&lt;FirstName i:nil="true" /&gt;
  </code></pre>
  
  <p>Does that mean something different than:</p>
  
  <pre><code>&lt;FirstName /&gt;
  </code></pre>
  
  <p>If so, what is the difference?</p>