Until (if) the online users feature is enabled again if you're really worried about seeing if someone is online or not, add the user to your buddy list.

Add users to list: https://www.vadriven.com/forums/profile.php?do=editlist
See who's online: https://www.vadriven.com/forums/misc.php?do=buddylist

This was disabled as per Jelsoft's suggestion as something to reduce loads (why the server is slow/down as of late).