[NeilFawcett]

Originally Posted by sonata

Have you implemented your idea. Do you mind to sharing some of your codes like how to check lastactivity and the session time out? I don't know how lastactivity is computed and saved in vbulletin. Thanks in advance.

Afraid not...

The variables of interest in the session table are:-
session.lastactivity
session.userid
Not sure what the session id field is called in the session file off the top of my head...

This following code returns all users currently online (ie: last activity > a cut off date)

	$datecut      = TIMENOW - *expiry age (eg: 300 secs?)*;
	$UsersOnline = $db->query("
		SELECT
			user.username, (user.options) AS invisible, user.usergroupid,
			session.userid,
			IF(displaygroupid=0, user.usergroupid, displaygroupid) AS displaygroupid
		FROM " . TABLE_PREFIX . "session AS session
		LEFT JOIN " . TABLE_PREFIX . "user AS user ON(user.userid = session.userid)
		WHERE session.lastactivity > $datecut and user.userid > 0
		" . iif($vbulletin->options['displayloggedin'] == 1, "ORDER BY username ASC") . "
	");