The service, powered by Tennessee startup PassAlong Networks and scheduled to premiere Thursday on EBay, lets customers share samples of their favorite tunes with friends and neighbors. And for every 10 songs that those friends purchase, the sender receives a free song.

PassAlong Network's service doesn't come close to duplicating the freewheeling, Kazaa-style song swapping that prompted the recording industry to slap thousands of copyright-infringement lawsuits on individual Internet users in the past year.

But PassAlong and EBay are trying to capture the same "excitement of sharing and experiencing new music,'' said Dave Jaworski, the company's founder and chief executive.

San Jose's EBay, which has 114 million members around the world, is joining a crowded field. A long list of technology giants have entered the increasingly competitive online music business, including Apple Computer, Microsoft, Sony, Wal-Mart, Yahoo, Napster and RealNetworks. And Wednesday, onetime Bay Area online music pioneer EMusic Inc. revamped its service.

EBay has started a six-month pilot program to "test the viability of EBay as a marketplace for digital music,'' said EBay spokesman Hani Durzi.

San Jose's IHoopla Music, which specializes in songs from independent artists, has already opened a store on EBay.

PassAlong Networks has signed deals with the four biggest record labels to offer 200,000 songs from popular artists such as Avril Lavigne. PassAlong plans to expand that catalog quickly to 500,000 by the end of September.

Songs can be downloaded for 99 cents each or for 9.99 per CD, prices comparable to competing online music services. But PassAlong members can also e-mail an Internet link that lets their friends hear a 30-second sample of a song.

The sender receives 10 points for each song and 100 points for each album that the receiver also buys. And for every 100 points, the sender gets a free download.

"It is a clever idea to enlist your own customers as salespeople,'' said Josh Bernoff, a principal analyst for Forrester Research.

"This is one of those things that is either going to be a big success or a flop. It's not going to be in the middle.''

Another Internet Web site is using the power of music as a draw.

MySpace.com, a social networking site based in Los Angeles, on Tuesday offered its 4 million users the chance to listen to a streaming audio version of rock group R.E.M.'s new CD two weeks before its official release in stores.

The album, "Around the Sun,'' went online Tuesday morning and had more than 200,000 hits that day, said Chris DeWolfe, co-founder of MySpace.com.

E-mail Benny Evangelista at bevangelista@sfchronicle.com.

This article appeared on page C - 3 of the San Francisco Chronicle