Yeah, the big number on the right is the number of currently active users (you can pick which metric you want though). On the left you get two other metrics, like users, new users, page views, conversions, etc.
Is this being tracked by each device?
I'm interested in my usage out of curiosity, and I'm able to see the info from my home router. I can use glasswire to track my windows devices and pinpoint services using the network. The router is currently my only way to see other home devices such as the cable box/tv/chromecast/nest.
If I could upload a log from my router, then this would be a nicer view. But I also don't want to upload too much data to a 3rd party...
Shoot, you're looking for a feature that won't be available until Apple approves my latest build, hopefully later this week. Sorry about the false advertising, I updated the site a bit early!