title: $_POST Array on servers running multiple sites
body: <p>How do the servers deal with the PHP arrays like: <code>$_POST</code> for example.
  Is the array going to be treated separately between websites (in case of multiple websites running on the same server)?</p>
  
  <p>For example, if I have website A and website B on one server, and both websites use a <code>$_POST</code> array with the exact same parameters names, is this going to cause a problem when 2 users accessing website a and the other website b at the same time and both requesting values from the <code>$_POST</code> array?</p>