title: What is the use for IHttpHandler.IsReusable?
body: <p>I'm writing a <code>IHttpHandler</code> and I'll need to implement a <code>IsReusable</code> property. When I look at the <a href="http://msdn.microsoft.com/en-us/library/system.web.ihttphandler.isreusable.aspx">MSDN documentation</a> it says: </p>
  
  <blockquote>
    <p>Gets a value indicating whether another request can use the 
    IHttpHandler instance.</p>
  </blockquote>
  
  <p>This isn't very helpful. <strong>In which situations should I use a reusable handler and in which situations should it not be reusable?</strong></p>
  
  <p>Follow up questions:</p>
  
  <ol>
  <li>What is reuse?</li>
  <li>Can I maintain state (i.e. class variables) when <code>Reusable = true</code>??</li>
  </ol>