Rap Genius today launched an official iOS app that lets users dig into the site's massive archive of song lyrics, poetry, news articles, and other text, along with the many annotations that have been added by the Rap Genius community. "This app has long been our users’ most-requested feature, and we’re pumped to finally deliver," said co-founder Tom Lehman. The company — fresh off a temporary rift between itself and Google — boldly describes its Genius mobile app as a "pocket guide to human culture." According to Lehman, it represents something of a new beginning for Rap Genius. "This is the true launch of Rap Genius," he said. "Right now, more than half of our traffic comes from mobile devices. Soon, it will be 100 percent."

Once you install Genius, it will immediately pull together lyrics for all of the music in your iPhone or iPod touch library. The app also includes a Shazam-like feature that instantly offers up annotated lyrics after briefly "listening" to and identifying music that's playing around you. Unfortunately for Android users, Genius is yet another app that's launching first on iOS — with no firm release date for Google's mobile OS. There's also no iPad version at this point. Genius is available now as a free download from the App Store.