title: Determining a unique user (w/o cookies, ip address) using PHP
body: <p>This is a very broad question; I'm just looking for the best way to do it.</p>
  
  <p>I want to be able to differentiate a <strong><code>unique user</code></strong>. I need to be able to track when a user visits a specific page.</p>
  
  <p>Here are the problems that I and other people have encountered :</p>
  
  <ul>
  <li>Using an <code>IP address</code> is not effective because there might be many computers on an <code>IP address</code></li>
  <li>Using <code>COOKIES</code> encounters a problem if the user clears his/her cookies in a given period of time.</li>
  <li>Using <code>SESSIONS</code> encounters a problem if the session expires.</li>
  </ul>
  
  <p>I am considering a combination of all three, but I'm still pretty sure this will not catch all the exceptions. I need a system similiar to the way <em>Youtube</em> tracks views on their videos.</p>
  
  <p>Does anyone have any other ideas to this? (Aside from implementing a user system)</p>