The Traffic meter is always located at the top left of the Now dashboard in GoSquared Analytics. It shows you how many visitors are concurrently on your website right now.
The traffic meter shows you how many people are online versus the 7 day minimum and maximum - so you can quickly see how well you're doing right now compared to your best and worst moments in the last seven days.
The "Visitors Online" metric is intended to be a true representation of the number of visitors concurrently on your website.
So for example, if you have 5 people in a room, and they all go to your website at the same time, GoSquared will show "5 visitors online". If 2 then leave, then GoSquared will show "3 visitors online". If they all leave, then GoSquared will show "0 visitors online".