It's not every day we see Windows Phone being used to launch a major new feature, but Twitter has done just that. An update to its official app has just enabled automatic translation if you happen to be reading a person's tweet that isn't in English. The tweet isn't translated in your actual timeline; instead you have to manually click through, but that's nothing to complain about. Microsoft's Bing Platform, also released yesterday, is likely being used as the backend, so this feature could very well come to Twitter's official apps on Android and iOS (not to mention a whole range of other apps) in the near future.
Bing Translator in Twitter for Windows Phone