I disagree. The goal of the interface should be to be ergonomic. In the case of the Kindle, there are a very small number of things that need to be memorized be

I disagree. The goal of the interface should be to be ergonomic. In the case of the Kindle, there are a very small number of things that need to be memorized because they have no visual cues. The small number of actions coupled with the fact that any visual cue would distract from the primary purpose of the device (to display text) make the current interface more ergonomic than one with always-present visual cues IMO.