Amazon Hears the Future, Buys sees where the future of media is heading, and is slowly amassing the properties and contracts it needs to make sure its retail empire is at the forefront. Today’s $300 million agreement to buy digital audio book reseller is just another milestone in a string of deals that Amazon believes will take it from books to bytes.

In May of 2000, Amazon named Audible its exclusive audio download partner and began offering Audible downloads, which are also available on iTunes and through the Audible web site. Audible had 446,000 users as of the end of September, which means Amazon is paying about $673 per customer to snag people who are comfortable using MP3 players and other devices to download DRM-protected music. Getting a lock on those users and Audible’s content could be a boon to Amazon as it moves forward with its Unbox and other digital strategies. I have called Audible to find out what happens to its iTunes relationship, which is where it sells many of its downloads. Check back for updates. Update: Amazon PR got back to me to say that Audible will continue to sell content via Apple and hopes to grow the relationship.