“[An Extended] interface adjusts to the screen’s size, adding or subtracting layout components according to the dimensions of the chosen orientation. For example, IMDb for the iPad uses the wider screen in landscape mode to add a filmography on the left. This list is also accessible in portrait mode by clicking the “All filmography” button in the middle-right of the screen.”

Link: Designing For Device Orientation: From Portrait To Landscape (smashingmagazine.com)