Domain Users shows end-users with the most traffic in one domain.
To see this view, go to Top N > End Users option and select certain domain within All Users node.
Figure above example of top end-user traffic from domain DOMAIN1 in time period of 6-hours, ordered by Total Average traffic.
This view to see how much traffic passing through a specific domain. Main Panel can show Throughput or Volume measured in bits, packets or flows.