title: Unique ID with time()
body: <p>If I use:</p>
  
  <pre><code>$t = time();
  echo $t;
  </code></pre>
  
  <p>This will output something like: <code>1319390934</code></p>
  
  <p><strong>I have two questions:</strong></p>
  
  <ol>
  <li>This value can be used as unique id ?</li>
  <li>how to generate from it a date?</li>
  </ol>
  
  <p>I can't use <code>uniqid()</code>, because I need a value that can be used to order (recent).</p>