-- iTunes? Old news. Radio? Ancient history. Buying a new CD? Maybe every now and then.

But the most popular way today's teens discover music is through clicking around on YouTube.

That's the finding of a new study by media research firm Nielsen. Its Music 360 report set out to learn how music is found, purchased and consumed.

Among all adults, radio remains the most popular tool, with 48 percent saying that's how they usually discover their new jams.

But more teens, 64 percent, cited YouTube, the Web's leading video-sharing site, as a place where they listen to music. Followed by radio (56%), iTunes (53% ) and CDs (50%).

The popularity of YouTube is dramatically higher among teens than all adults. Only 7 percent of all respondents said they discover music most frequently through the site.

Strangely, the report doesn't address teens' listening habits on music-streaming sites such as Pandora, Spotify or Grooveshark.

"The accessibility of music has seen tremendous expansion and diversification," said David Bakula, a Nielsen senior vice president. "While younger listeners opt for technologically advanced methods , traditional methods of discovery like radio and word-of-mouth continue to be strong drivers."

The study also shows the changing landscape of music sales. Just over one in three teens (36 percent) said they'd bought a CD in the past year, while more than half (51 percent) said they'd paid to download at least one song.

The report came from an online survey of 3,000 people in the United States.

Among all respondents, finding new music still relies upon a mix of new media and more traditional means.

In addition to the 48 percent who favor radio, 10 percent said they rely on friends or relatives for suggestions. But more than half (54 percent) said those personal recommendations make them more likely to make a purchase.

YouTube, which is owned by Google, claims more than 800 million unique visitors every month. More than 3 billion hours of videos are viewed each month and 72 hours worth of video are uploaded every minute