it's great you are taking the effort to create this document. Some feedback:
Home Button - this takes you back to the starting point in a synth (if your're ever lost in a synth you can click this to go back to the beginning). When you create a synth initially the synther chooses and image it feels is the best starting point, but then you change change this starting image in the Photosynth Editor application.
"So – even though this process is consuming colossal amounts of computing power, this processing is being done at Microsoft and is being streamed to you over the internet." - The actual 3D reconstruction happens on your computer, the application where you select the photos to include is called the synther and it reconstructs the 3D scene on the users computer, no computing power is required on the Microsoft servers to reconstruct the scene.