iosnewsstandspringboard
Newsstand seems to be a fancy folder, contianing specific apps. Normal folders on iOS have a limited number of apps which they can contain.
Does newsstand inherit this limit, or does the scrolling shelf bypass this limitation? Is there a hard limit to the number of apps that one can have installed in Newsstand?
Screen A that you refer to is the original 'Apple' home screen. Your observation is correct. The only time an app will install on screen A is when it is already present (or moved by you) and you are updating to a newer version of the app.
All other new apps will be installed in the screen closest to what you define as Screen A when possible (i.e. if Screen B is already full, it will go to screen C and so forth). New apps will never get installed into folders (unless you update the app that is already within a folder)
I understand it to be limiting the type of information apps are allowed to track about you. Specifically, they shouldn't store your UUID.
For example, apps could associate your UUID with behaviors you demonstrate in the app and so provide targetted marketing. The idea of behavioral tracking and targeting are discussed on this World Privacy Forum page.
The upshot is that if you enable privacy, apps shouldn't provide tailored (targetted) adverts to you based on what you do in their apps. I'm not sure how it'll be enforced though; perhaps, it prevents access to your UUID, but I'm not sure if that'll be for iAd apps only.
The "Learn More" link at the bottom of your screen gives some explanation in Apple's own words. The non-personal reference I think is about anonymising your UUID (so it can't be traced back to you personally) but in essence its still a UUID.
I'm sorry I don't have more specific information about the implementation but hopefully this sets the scene somewhat.
Best Answer
It's a shelf for a lot of subscriptions. Many more than the standard folder limits. As conceptually you could see it as a folder, but in fact its a newsstand. I tried to find some documentation on the limit for newsstand and couldn't find anything but I've seen some of my clients have a LOT of subscriptions on their shelves.