Best data combination to ensure web user uniqueness?
<p>How to ensure that the anonymous web users that voting using your poll-system are unique (<em>each anonymous user votes for once only</em>)?</p>

<p><strong>I can think of:</strong><br>
 1. Client's IP Address<br>
 2. Client's Machine Name<br>
 3. MAC Address<br>
 4. Storing cookie</p>

<p>As far as I know, you cant get (2) &amp; (3) in web development, and (4) is not guaranteed since user can delete/not allow cookies</p>

<p>what do you think is better to achieve uniqueness?</p>
