One thing is that different communication programs are different "spaces" - you tend to associate one with one kind of thing for certain people, another with another. People-centric is really just one instance of document-centric, the "people" just being the data associated with the person. I suppose these icons on windows phone with different apps that can be opened from them are basically Windows's "open with". Android's dialog you get when opening a data url is the same letting you choose what app to open it with, such as if multiple apps are associated with phone numbers and you open a phone # from your contacts app.
