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As suggested in reports last week, Twitter on Thursday launched Twitter Music, a music discovery service for Web and iOS users.

In a blog post, Stephen Philips, founder of We Are Hunted, the music startup acquired by Twitter last year, said the service will change the way people find music.

"[Twitter Music] uses Twitter activity, including Tweets and engagement, to detect and surface the most popular tracks and emerging artists," said Philips. "It also brings artists' music-related Twitter activity front and center: Go to their profiles to see which music artists they follow and listen to songs by those artists."

The concept is similar to other music discovery apps, like Aweditorum, available for Apple's iPad. However, music discovery is not the same as music sales.

[ What can we expect from Apple's next smartphone? Read Apple iPhone 5S: Best And Worst Rumors. ]

Twitter Music provides partial access to songs from iTunes. The service presents a grid of images representing music artists that link to preview length snippets from iTunes. When clicked (or touched using the iOS version), the artist's song plays and a floating control panel provides buttons for buying the track in iTunes or composing a tweet that links to the song and includes the #NowPlaying hashtag.

Twitter users who also subscribe to Spotify or Rdio can log into their accounts to hear full-length versions of songs.

This isn't about revenue for Twitter, at least at the moment. It's about making Twitter more useful and more vital. If and when Twitter goes public, perhaps revenue will become more relevant. But the company is doing well enough that it doesn't need to worry about revenue immediately: According to eMarketer, Twitter will earn $582.8 million in global ad revenue in 2013 and will approach $1 billion in 2014.

Like photo sharing and storage, some form of music service appears to be obligatory among the major platform companies. Facebook has partnered with Spotify and offers other music apps as well. Microsoft last fall launched Xbox Music. And Amazon, Apple and Google are all said to be developing music services. Despite the fact each of these three already operate online music stores -- the Amazon MP3 Store, Apple iTunes and Google Play Music -- none of them offer a streaming music service or leverage social networking very effectively.

Apple tried creating a social music service called Ping, which launched in September 2010 and shut down two years later.

Twitter Music is currently available in the U.S., Australia, Canada, Ireland, New Zealand and the U.K. According to Philips, Twitter is working on an Android version of its music app and is planning to launch Twitter Music in additional countries.