Our tracking data from the end of last year shows that the size of the music downloading audience is larger than ever. In the American adult population alone, some 37% of internet users say they download music files online and 7% do so on a typical day.

It’s also the case that music fans have more choices than ever when it comes to digital downloads. While iTunes continues to offer most of its standard tracks for 99 cents per download, consumers also have the option to pay extra for DRM-free files. Amazon offers MP3 downloads free of DRM, and subscription services like eMusic have made DRM-free music a foundational part of their business model from the outset.

One of the later arrivals to the DRM unmasking party was Wal-Mart, which nudged its way into the music market by offering 94 cent MP3 downloads beginning in 2007. However, as blogger Cory Doctorow noted in a recent post, if you purchased any of Wal-Mart’s DRM-protected music anytime before February 2008, you may soon find that those files are no longer playable. Wal-Mart recently announced that they would no longer be able to assist with digital rights management issues for protected WMA files purchased from Walmart.com. If users don’t back up their files before October 9th, they will no longer be able to transfer songs to other computers or access songs after changing or reinstalling operating systems or in the event of a system crash.

All of this uncertainty over the stability of digital files has some music consumers turning their tables back to the pre-download, pre-compact disc vinyl format. Artists such as the White Stripes and Cat Power have been releasing their albums on vinyl and there are signs that demand among serious music collectors is growing.

To be sure, records won’t be the magic spinning bullet that reverses the decline of a struggling industry, but in the age of digital ephemera, those of us who still consider music a long-term investment may start to prefer the steady reassuring crackle of vinyl to a “file not found” message.