Im not sure about the domain terminology. But, I guess it would be in the domain. I have attached a quick sketch of the model I am working with. I am trying to determine the average air velocity in the room.
The Summary file will give you the Statistics for velocity through the entire domain (in other words the whole model).
What I was referring to with the previous question was if you wanted data for the whole model or perhaps a small corner that you were interested in.
For a more local average you can use Cutplanes (and its ability to save out csv data), or XY plots.