Ready for implementation
A View shows details about a particular content item or visualises item collections. Examples are the content preview and the visualisation of the page hierarchy of a site in AdminCentral. Views, in general, should have their own URI so that they can be easily bookmarked and re-used. Views may also contain other views.
A Layer is a high-level construct and consists of one or multiple views as well as additional interface elements and controls. The central idea behind layers is that they are orthogonal to each other: only one is visible at a time; you may leave one layer for another and the original layer keeps its context. So layers are organised on a stack. Layers on the stack are in the same state when you return to them as when you've left them.
A good example of a stack of layers in Magnolia is page editing. When you edit a site, you're in layer 1 consisting on the AdminCentral interface. If you open a page for editing or preview, the page editing layer (layer 2) appears and takes over the screen. Layer 1 is put on the layer stack and preserves its state. As soon as you either save your changes or cancel editing, layer 2 disappears again and actually releases its resources - the layer 1 gets visible again and is in the exact same state as when you left it.
The list of possible layers - this has not yet been looked at in all detail - contains Admin Central, page editing, versioning of pages, translation of pages and A-B testing.