Now that Sony BMG has decided to join the revolution inspired by the “Down with DRM” slogan, Amazon MP3 Store has found itself, less than six months after its launch, in the position of iTunes’ most potent adversary.

Will Amazon succeed though in seizing a part of the 70 percent share of the digital music download market that iTunes holds at the moment?

Ever since 2003, when the iTunes Store was officially launched, Apple’s supremacy has been based on the iTunes + iPod combo. Music downloaded from iTunes only plays on an iPod, thus helping sales raise on both segments. The more iPods sold, the more songs bought off iTunes and so on.

From this specific perspective, Amazon MP3 has one certain advantage. As all songs it sells are DRM-free, these can be downloaded and played on any device, from the iPod’s direct adversary the Zune to any PC that has Windows installed. The number of consumers Amazon can attract is potentially much larger than the one iTunes currently has.

In addition, Amazon’s aggressive pricing policy through partnerships with the four major music studios gives it a much better position compared to Apple.

Is this the end of iTunes’ domination of the digital music market? Over the past years, numerous MP3 makers and Internet portals have aspired to release devices and/or stores that would bury iTunes and the iPod.

Amazon now appears to be coming closest to actually avenge all who have ever envisioned themselves to be iTunes, iPod killers. How will Apple address the situation? Will it try to lower the price on its songs or iPods? Will it try to reach deals for DRM-free distribution?

These days Apple seems to be embroiled in a much more important battle: convincing movie companies to join iTunes. Video content is the hottest and should Apple succeed in replicating its present success in the music industry in that of the movies, it would be a grand victory that would entail a different level of profits than those registered in the music business.

Even if Amazon wins the battle over music, the triumph may come too late, as there is already a new domain to be fought over.