The survey by market research firm NPD Group found that approximately 1.7 million U.S. households downloaded a song from iTunes in March. That was good enough to earn the store a second-place ranking with peer-to-peer downloading service LimeWire.
The most popular digital music service during the month, however, was P2P site WinMX, which was used by 2.1 million households to download music during the month.
"One of the music industry's questions has been, when will paid download stores compete head-to-head with free P2P download services?" Russ Crupnick, president of the NPD Group's music and movies division, said in a statement. "That question has now been answered. iTunes is more popular than nearly any P2P service."
On NPD's list of the top 10 digital music services, iTunes was ranked ahead of file-sharing companies such Kazaa and iMesh. Other paid online music services such as Napster and RealNetworks' RealPlayer store also edged onto the list.
"These (paid) digital download stores appear to have created a compelling and economically viable alternative to illegal file sharing," Crupnick said.
According to NPD, about 4 percent of Internet-enabled households in the nation used a paid music download store in March.
Most of those who prefer legal music download sites are over 30 years of age. But many younger consumers still resort to sharing files over peer-to-peer services, NPD said.
Congress passed legislation to curtail piracy on file-swapping networks in April this year. And the Supreme Court is critically analyzing file swapping and is expected to rule on its legality soon.
