A week ago today, WSJ led the Marketplace Section with an article headlined, “Online Music Rings Up New Sales With Outtakes, Mixes” [sub. needed]. The piece talks about how songs that will never make it on a CD are ringing up huge sales online.

A day after singer Beyonce belted out her soulful interpretation of the anthem at this year’s Super Bowl, the recording was up for sale for 99 cents on Apple Computer Inc.’s iTunes Music Store, where it became one of the top-selling tracks for the week.

and

Last month, Apple put a version of “I Fought the Law” by rockers Green Day up for sale on iTunes at 10 p.m., after the song aired earlier that day as the soundtrack to a Super Bowl commercial for Apple and PepsiCo Inc. For the next two weeks, “I Fought the Law” was the top-selling track on iTunes and, since then, has bounced around the top three or four slots.

Rob Schoeben, vice president of applications marketing at Apple, says the Green Day track is a “world-wide exclusive” on iTunes, meaning it won’t appear on other Web sites or in stores. Apple believes Internet-only music may be an important way to coax first-time users into buying their music on the Internet. “We think if there are things you can only get online, you can get people who are laggards to try online” music buying, Mr. Schoeben says.

I think both of these illustrate the idea I was talking about last week. If people hear something they like, they want to be able to go buy it right away. By offer these tracks, iTunes are filling that need and creating a unique revenue source that didn’t exist before.

BTW, I don’t buy the laggards argument.