title: C# xml documentation
body: <p>What's the purpose of the <code>.xml</code> documentation files shipped with the assemblies (<code>.dll</code> files).</p>
  
  <p>I know, how to build a one (<a href="http://msdn.microsoft.com/en-us/library/aa288481%28VS.9.0%29.aspx" rel="nofollow">as here, for example</a>), but what can they be used for?</p>
  
  <p><em>Also, if this documentation can be integrated into the MS Visual Studio environment, how should that be done?</em></p>