If I'm discussing Apple TV, I'll start by using simple old-media analogies that stick, saying it's like Cable-VOD or a stack of video tapes by your TV. The important thing, I think, is that you have to (at least first) gloss over nuances. Then it is a matter of layering artful examples to try to cover what Apple TV does. It is like picking the right brushes (= small analogies) to paint a familiar scene, rather than constructing a consistent argument from first principles.