Great idea Barcey
Not exactly an analogy, but just as silly imho:
Buy music online. Simply download our proprietary music player software and get connected to our online store. From there you can download any of our 1.2 million songs available in our own proprietary DRMed audio format. All you need to take the songs with you is our mp3 player, then simply transfer the songs to this player. Just make sure you backup the music downloaded, if you don't and you happen to lose your copies of the songs you won't be able to download them again.