In case you've gone through life so far while being blissfully unaware of the phrase "reality augmentation" — well, today's your lucky day. Or something.
Michael Zoellner's TwittaRound (currently in beta testing) enhances the iPhone 3GS Twitter experience by utilizing the phone's compass and accelerometer GPS to show you nearby Tweeters. The video above tells you more about the app.
What it doesn't you is that apps like these use non-public API's to perform their video tricks — so don't expect to see this in the App Store anytime soon.