New ad-based 'free' content model challenges iTunes

In a major shift in thinking, Universal Music, one of the world's largest music companies, has decided to back a Web site that allows Internet users to download its music without paying a fee.

The catch is that users will be subjected to advertising, constrained to certain playback devices and required to periodically return to the home Web site to maintain access to the music.

Universal Music will back a new online venture called SpiralFrog, which is set to begin operations in December. The service will compete with Apple's popular iTunes, an online music and video store that currently charges 99 cents per downloaded song.

Users of SpiralFrog will be allowed to download an unlimited number of songs from Universal's catalog to their computer and one other device. But they will be prohibited from burning the songs to a CD, and they must visit the SpiralFrog site at least once a month to maintain access to their previously downloaded music.

Three other major labels — Warner, EMI and Sony-BMG — have been approached about joining the site. Perry Ellis, the fashion company, has committed to advertise on SpiralFrog, while Levi's, Benetton, Aeropostale and others have reportedly expressed interest as well.