I noticed at work, where we are all behind a proxy server, people would get cached versions of my site. This was disturbing because other employees could view private threads. I added this to the dootput function in functions.php right under the global declaration to prevent this:
PHP Code:
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") ." GMT");
header("Cache-Control: no-cache, must revalidate");
header("Pragma: no-cache");
header("Cache-Control: post-check=0, pre-check=0");