(The modest eight-hour battery life between charges is one of the few regular complaints from iPod owners.)

Some iPod owners can be very picky.

Apple is offering only $20 per device, based on the statistic that the typical iPod owner only buys an average of 20 tracks from the store.

Ask a group of iPod owners what percentage of Americans own iPods, and they will usually overestimate.

Some estimates suggest that 85 per cent of iPod owners listen primarily to music they have simply ripped from their own collections.

"Think of your traditional iPod owner," said a source.

Then the digital distribution channel, accessed via a desktop application used by every iPod owner.

Apple first unleashed iTunes in 2001 to help iPod owners manipulate their music collections.

But this would force every iPod owner to download new software.

Ms. Keane's service is one of a few enterprises formed to serve iPod owners.