The gesture is only half the battle though, you need appropriate feedback. Once the reload is activated, the scrollable area of the list actually changes to leave the feedback UI in-place (rather than bouncing offscreen). Without this part, the UI is unintuitive. And once the loading is complete, the UI makes itself disappear.

I don’t use Twitter very much so this app was brought to my attention by someone else, but it blew me away instantly. It’s rare for an application to generate so much discussion with a single point of UI, but it’s a real masterstroke for something that has such a high quality experience even without it. If you see one piece of interaction design this year, make it this one. (thx petervidani)