Rdio version 2.21 for iOS gets song stations, autoplay

Rdio, the streaming service that hates the letter a, has updated its iOS app to help users find new, yet similar, music. Song Stations will generate playlists from a single artist, which folds in related music as it goes. The feature will let you preview the next four tracks in the list, giving you the power to skip as many time as you like -- just in case you find yourself trapped in a singer's middle-period creative slump. Rdio has also added autoplay to the app, so when your current playlist has ended, it'll find something similar to ensure you're never plunged into an awkward silence.