That was part of the Chat plugin for the menu bar tab. We updated vBulletin and are now using vBulletin's core to produce the tabs. Part of the problem we were having were exploitations to the site through these plugins. I am very bullish on plugins because of this, as well as making it a bigger headache every time an update is done you have to make sure the plugins remain working. You'll just have to scroll down to see who's in chat now.