Rdio, the popular Internet radio service, has just pushed a long-expected update that has finally enabled a music recommendation engine in its iPhone and iPad app. Fans will remember that the inaugural 1.0 build had that useful feature front and center.

Unfortunately, it was inexplicably pulled as the company started experimenting with stuff like Pandora-stylepersonalized Stationsand got busy implementingsocial featuresandotherenhancements.

Rdio 2.5.3 for iOS (iPhone screenshot 002)

It was a little over a month ago thatRdio confirmed plansto bring back the popular music-recommendation capability and today they’ve made good on that promise…

Pitched as a new destination for discovering what to play next, Recommendations in Rdio lets you find albums similar to what you’ve been listening to. Even better, the feature will recommend Stations and playlists popular with your friends or in your area.

Rdio 2.5.3 for iOS (iPhone screenshot 001)

It certainly goes a long way toward exposing folks to new music they may not have been aware of and should allow for a better experience, one that’s on par with Pandora and iTunes Genius. Rdio Recommendations are also available in the web interface.

The feature works on auto-pilot by automatically analyzing what you listen to most and who you’re following in order to suggest albums, stations and playlists you might like.

Rdio 2.3.3. for iOS (iPhone screenshot 001)

The recommendations are powered by Echonest, which taps a database comprising a whopping 35 million songs to provide music recommendations to the likes of Spotify and BBC, for example.

The new Rdio software arrives hot on the heels offthis morning’s Spotify refreshwhich has brought out such nice-to-haves as artist tour details via Songkick, much improved search with instant results, the ability to search across profiles and playlists and more.

Other new features in this Rdio release include visual tweaks, bug fixes and a redesigned Stations player whose three-track display now showcases album art for the previous, currently playing and next tracks.

You can just swipe on the Stations player to skip to the next track.

Rdio can be downloaded free of charge from the App Store.

The universal binary requires an iOS device running iOS 5 or later and one of the paid Rdio Unlimited tiers, available through in-app purchase.