Not the iPod as it is used, but the iPod as it can be used. The iPod (with earphones)...
1. Destroys the concept of background music. Making music sound good is dangerous. Once our ears hear something pleasant, we can start to think that we understand the music. Music is meant to be pleasant, and the best music, the most pleasant—but when pleasure is extracted from the High music the same way pleasure is extracted from popular music, two things happen. (1) Popular music will always win (as it should, if that is the competition), and (2) High music becomes disappointing.
The iPod and similar technologies change all that. With the iPod's earphones pushed firmly in your ears, the music demands your attention. As C. S. Lewis says about art, "We sit down before the picture in order to have something done to us, not that we may do things with it. The first demand any work of any art makes upon us is surrender. Look. Listen. Receive. Get yourself out of the way." Not that I would suggest that a picture is better appreciated by looking at it with your nose touching the canvas. The iPod with earphones is preferable to CD players and computer speakers because it is far closer to the experience of live performance.
2. Is less individualistic and more corporate than music on a CD player. The iPod makes you aware of the performer. Your left speaker plays certain sounds into your left ear, and your right speaker plays certain sounds into your right ear. With this, you get a sense of distance between the players. This is fantastic. It's a constant, conscious or subconscious reminder that music is a communal thing.
3. Replaces music as a science. That teenager, doing the closest thing to lying down that you can in a chair, eyes on vacation and slobber collecting on his lip. Yeah, him. He has earphones in and he understands about popular music what Classical musicians don't understand about their music. We think he's rude when it takes yelling at him to pull him out of his musical seance. He probably is. But what if, instead of our caricatured teenager, we have someone whose profession in life is the study of J. S. Bach. Suddenly, the fact that it takes yelling to get him out of his iPod infatuation is a good sign. Like the college student engrossed in his calculus. Or biology. Or history. Or Latin.
4. Teaches you about poetry. I was listening to a 12th century Christmas song on my iPod when I realized the guy was singing in Latin and I recognized the words. The iPod managed to remind me that it was just as sensible to say that I was hearing poetry as to say that I was listening to music. That sound of the saliva from the singers' dentals and labials can be heard much more deliciously when they're spat right onto your eardrums. Again, it's more like live performance.
5. Teaches you about ambience. Just like HD TVs can show you the pores on your favorite news anchor's face, the iPod lets you hear all the gory details of the music without everyone yelling at you to turn down the volume. Why is that an advantage? Yes, you guessed it. It's more like live performance. The iPod teaches you that music isn't on paper.
6. Teaches you about liturgy. Liturgy assaults the senses. It comes from all sides. That's what makes a football game so fun. When you listen to a Bach oratorio on an iPod, it's like a football game. Like I said in #2, you feel distances. You hear the details. You sense the contour. Texture is a thing only the best Bose speakers can emulate for a CD player. For an iPod with earphones, it's the name of the game. Antiphony, cyclicality, and juxtaposition are all heightened with your earphones.
7. Teaches you about polyphony. This was, to me, the most shocking and delightful thing about my iPod. At last I could hear mimesis. Out of my left ear came the soprano doing a motif, and then from my right ear a bass doing the same motif an octave lower. The iPod cheerfully murders the idea that counterpoint is beautiful only on paper. Ahh, I thought. It's almost like I'm there. Now, tell me you can hear the counterpoint on your CD player like that.
8. Teaches you about conversation. Mortimer Adler said Western civilization was engaged in a Great Conversation. Well, he was right, about music, anyway. The iPod imposes canonicity. You can move your thumb a centimeter and flip over centuries. Think of how that can change perception of music. It's the difference between having a Bible made up of separate scrolls for each book and having a Bible in one leather-bound volume. What's that do you to your understanding of theology? A lot.
9. Teaches you criticism. On my iPod, I have six (6) different recordings of Ravel's La Valse. I can put them all on a playlist and listen to them one after the other. Why would I want to? Well, they all just do that climax wrong. Simon Rattle goes slow enough that you lose the waltz. Pierre Boulez just drags. Charles Munich goes too fast. Bernstein is almost right—the trumpet crescendo is brilliant—but, there's just something. Hm.
10. Teaches you humility. My iPod Nano is smaller than a baby's foot and can hold 8 GBs of music. Yahoo answers says that's 2000 songs, which means that it can probably hold about 800 of mine. The "Cover Flow" feature is enough to remind me that there are galaxies of music I haven't visited, and I can flip through them with my thumb. It's a humbling thought. And fun.
(11. There's this cool game on my iPod called Vortex...just kidding. This is all thanks to my cousin Madeleine, who decided I was just awesome enough of a relative to deserve an iPod for Christmas. You can blame my corrupted self on her.)