title: using WebClient and receiving Error 403
body: <p>I'm currently using <code>WebClient</code> to open a few websites but after a period of time I start receiving <code>Error 403</code> messages.<br>
  I'm assuming it's because I'm hitting their servers to frequently/quickly.  I'm assuming all I need to do is add a <code>Thread.Sleep</code> time-frame between requests.  </p>
  
  <p>Since I'm having to do this a large number of times is there a suggestion on how to handle the throttling issue without have to take a tremendous amount of time?<br>
  For instance 3 secs between requests will end up taking me like 3 hrs to do.</p>
  
  <p>So the question is, is <code>Thread.Sleep</code> really the right solution for this?  and if it is, what is a good time-frame for it?</p>
  
  <p>As a side note I have also used <code>HttpWebRequest</code> and ran into the same problem.  I do still use it in other code projects and technically am hoping to utilize the same solution (or close to it) for these other code projects utilizing the <code>HttpWebRequest</code></p>