The largest U.S. radio broadcaster has begun tagging tracks played on its 340 digital radio stations in order that they can easily be purchased through iTunes.

Clear Channel Radio has added the tags to all its stations, meaning radio listeners can easily identify and purchase music they hear played on air. The deal means iTunes will consolidate its market leading position in U.S. music retail, while seeing Clear Channel take a slice of song sale revenue.

"Radio continues to be the number one way that people discover new music, and the HD Radio iTunes tagging capability lets listeners add songs to their iPod playlists with just a push of the button," said John Hogan, president and CEO of Clear Channel Radio. "With the vast majority of our HD primary stations now offering this exciting feature, we're demonstrating how radio's collaboration with the iPod benefits consumers."

Clear Channel Radio originally announced last September its intentions to offer broadcasts compatible with Apple's implementation of the HD Radio tagging feature.

The second-biggest U.S. radio broadcaster CBS, Entercom Communications, and other radio stations also plan to tag HD stations. "We are in full support of this technology and are currently working to develop an iTunes tagging strategy,' said Entercom spokesperson Emily DiTomo.

The new tagging feature only works with digital radio receivers that support the HD Radio tagging feature, such as Polk Audio's I-Sonic Entertainment System 2.

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