In the list of users online at the bottom of the main page? As in this snapshot:
I've only ever seen one user at a time with the "+". I thought that it identified the moderators, but that doesn't seem to be the case.
Most users ever online was 698, October 31, 2006 at 08:19 PM.
Not Right in the Head, ADAM, Anaesthesine, billybrown, clarke41, Dave+, Dow Jones, drifter, Gay4Moz, Harsh Truth, HIM, jackson, Jones, Jose, LASHAA, lovemorrissey, mozinmich, patten, RobLand, Samson, Skinner, StillILL, The Cat's Mother, TLOTFamousIP
I've only ever seen one user at a time with the "+". I thought that it identified the moderators, but that doesn't seem to be the case.