@Lukew in Mobile First: “When holding a touch phone screen with only your right hand, it’s easy to hit the dark green area and a stretch to tap the yellow area with your thumb.”
37 Signal’s Basecamp’s mobile login form keeps labels within input fields visible until a user actually begins to enter an answer. via @LukeW - Mobile First
Great example of a responsive site: Indie Energy
Goes beyond responsive resizing and optimizes content depending on browser size. (e.g. video and navigation placement). Highlighting content first on mobile (with primary nav below) is becoming a best practice trend.