title: What does dollar sign $ do in url?
body: <p>I have been reading that <code>$ ! ; . ,</code> are 'reserved' chars in url. But I can not find what are they reserved for.  </p>
  
  <pre><code>/ path delimiter  
  : port
  ? query  
  &amp; glue get params  
  = param=val  
  \# link anchor  
  + space
  </code></pre>
  
  <p>.   </p>
  
  <p>My <code>specific</code> questions:<br>
  Does anyone know what are <code>$ ! ; . ,</code> used for?<br>
  Does <code>:</code> have any special meaning in request uri?</p>