There's been a lot of talk about the huge first-week debut of Lil Wayne's Tha Carter III. Some are amazed an album can still sell in the digital age. Some cite free music -- P2P or self-released tracks -- as the key factor for the album's success. Those are good reasons, but it's not the most important factor. It's radio.

There's a good reason The Carter III sold a shade over one million in its first week of release, and Billboard's Fred Bronson brought it up in his "Chart Beat" column. Lil Wayne was featured in seven songs in the Billboard Hot 100 when the album dropped. Five of the songs are from Tha Carter III and two of them are songs by other artists (Usher and Lloyd) on which Lil Wayne appears as a guest. One of Lil Wayne's five Top 100 songs, "Lollipop," was at #1 for two weeks before dropping to #3 this week. Awareness for the album was sky high.

That much radio play means people have effectively sampled Tha Carter III before making a purchase decision. If you heard those five tracks that charted, you heard about a third of the album and have a pretty good idea if you're going to like it.

I'm going to get some disagreement, no doubt about it. The New Yorker's Sasha Frere-Jones argued that the abundance of Lil Wayne music released in 2007 was behind last week's sales bonanza.

This sales spike suggests that giving away music, far from destroying the music business, could be the gesture that saves it. More than a hundred free Lil Wayne tracks surfaced last year, many with Wayne’s blessing. Anyone at the Recording Industry Association of America who felt somehow safer and righteous when DJ Drama (Wayne’s closest mixtape collaborator) was arrested in Atlanta last year might want to revisit those feelings. Outlawing mixtapes is, in essence, firing people who are already working for free to promote your paid employee.

Digital Music News' Paul Resnikoff hit squarely upon the aspect of awareness. He focused on P2P instead of radio, though. That's close to the heart of the matter, but P2P is more a symptom than a cause. Radio is the main driver here, in my opinion. Without so much success at radio, the pre-release leak of Tha Carter III wouldn't have been as newsworthy an event and there wouldn't have been so many files traded. Radio (as well as widespread video play) is what raised awareness and pumped up demand.

As Frere-Jones pointed out, awareness was impacted by last year's flood of Lil Wayne tracks. Free tracks and mixtapes are a really good strategy of maintaining awareness in an off year. And the Amazon.com product page says Lil Wayne has appeared on over 70 songs since the release of his previous album. Free tracks and guest appearances, however, cannot by themselves create the sort of demand that can move a million units in one week. It's all too easy to look to the digital world and dismiss traditional (read: boring, old world) mass media, but in this case you'd be missing the story.