Really thanks for your reply. 
>Actually, the first link shows the model manager *data* on the Web Server box.
Yes. That's same understanding as me.
>The manager service and the DEM Orchestrator should be installed together.
I think "can" is more appropriate rather than "should".
If this is correct, the following sentence should be revised, right?
Distributed Execution Managers
>As for the naming, you will typically hear "manager service" used, but the service is listed as "vCloud Automation Center Manager Service" if you look in the services console in Windows. The DEM information is correct, I'm not sure what you think is out of date here?
OK. In this case, it's better to change the service name as latest name like "vRealize Automation Manager Service". However, it's acceptable for me not to change it because customers can guess the correct name somehow.
> The Web Server information is correct, but the line is a bit more blurry when it comes to understanding how it interacts with the appliance to deliver services.
As you said, there is blurry expression and it's painful to understand it. At least, it is feasible to write explicitly about Model Manager data or web and how this is interacted with other components, I think.
So it's appreciated if a person in charge could make clear it as far as he can. Writing it in informal site such as VMware blog is OK. If this is improved, it's helpful for more selling vRA to my customers.