In fact, I have three different music players. My desktop iTunes library contains nearly a terabyte of movies and music. My iPod has its 160-gig drive, and it's packed to the gills. And then I have my 16-gig iPhone. Yet when it comes to a simple question of the breadth of content, the listening experience with the iPhone is just about the same as what I enjoy with any other.

Why? Because practically all the content on my iPhone is managed with smart playlists. Instead of assembling static lists of music and videos, I have merely described the kind of stuff that iTunes should maintain on my phone at all times. iTunes keeps churning the content with each night's sync. So while my iPhone only has 16 gigabytes of storage, the net effect is that iTunes is projecting a constantly moving 16-gig window of content from a media library that's more than 100 times larger.

I mean, think about it: It would take me months of nonstop listening to go through all the stuff on my iPod. Which is nice, if you have the sort of job where you can take that much time off for personal projects, but I rarely go more than, say, two days before I dock my iPhone back to my desktop. Every sync is another chance for iTunes to close the curtains and make sure there's a whole new scene in place by the time the curtains rise up on the next act.

Figure 2-1 shows you a typical example of one of these playlists.

It's dead simple but awesomely powerful. You can translate this playlist's mandate as "This playlist should only contain music that I really, really like and that I haven't played in more or less forever." It selects only music rated 4 or 5 stars, and puts the least recently played tracks into the playlist first.

It's the last bit that delivers the punch. Obviously, since this playlist contains only awesome music — I've titled it "Only Awesome Music" just to underscore the point — I use it a lot in the car. But as soon as I get home and dock my iPhone, every track that I listened to during the 20-minute drive to MIT, the 20-minute drive back home, and the 73 minutes spent orbiting Cambridge looking for a parking spot, is removed and replaced with another top-favorite track that I haven't played in ages.

Obediently and without demand for acknowledgement or reward, iTunes keeps digging through your library, looking for lost treasures.

That criterion is also useful when it's set to maintain a playlist of your library's freshest content. It's particularly good at maintaining a playlist of new podcasts (see Figure 2-2).

Another dead-simple playlist: It just looks for tracks whose genre is "podcast" and chooses the most recently added gigabyte's worth, from among those podcasts that Ihaven't heard yet.

This approach is actually more useful than relying on the iPhone music player app's built-in Podcasts button. I think Apple's feature is way too ... too — sorry, which side of the brain is it that handles all the Spock-like logical thinking? It's too that side of the brain. When I jump in my car or go for a walk, I'm not explicitly thinking, "I'd like to hear every unheard new episode of the Bugle." I'm thinking, "Time to listen to today's new podcasts, whatever they are." I get the Bugle, followed by Martini Shot, followed by SMODcast, followed by ... etc.

Figure 2.3. Seeing stars: rating the music on your iPhone

I use these smart playlists to manage all my content. I do still have a handful of manual playlists — chiefly, a playlist of "must have" albums and videos that I always want to have handy — but everything else is selected and synced to my iPhone automatically.

I have about a dozen smart playlists covering every genre and situation, and by using the smart playlist's "Limit to X Gigabytes" feature, I can keep my iPhone partitioned. I always have 4 gigs of music I haven't heard in eons: 2 gigs of recently added movies, the latest 2 gigs of movies, 500 megs of jazz, 1 gig of classical, 1.5 gigs of rock, and a combined 500 gigs of country and bluegrass, leaving a healthy block of empty space.

This technique becomes much more powerful once you've started applying personal ratings to allll your music. Most people never get around to doing this, even though it's pretty easy. In iTunes, you just click your mouse in the Rating column next to the track, and assign it from 1 to 5 stars. On your iPhone, you tap the album art twice while the track is playing, and then illuminate the appropriate number of stars with a second tap (see Figure 2-3).

Figure 2.4. Hey now, you're a rock star. Or you will be, after putting this smart playlist into regular rotation.

But it's a pain to go through all of that for hundreds or even thousands or tens of thousands of tracks. A smart playlist can actually automate the entire action, viz Figure 2-4.

This smart playlist hunts for rock music that I haven't gotten around to rating. If I get in the habit of listening to this playlist as I take my morning constitutional and noting my galvanic skin response as the first chords ring through my headphones, I'll eventually get every last one of my rock tracks duly starred.

It's like dog training, really. There's a positive reinforcement/reward for taking a moment to tap the screen and register my opinion. This is the only playlist I listen to for the whole hour, and if I want that unrated Neil Diamond song to finally go away, the only way to accomplish that is to assign it an inevitable one, lonely star so that iTunes replaces it with something that I didn't buy as a joke.

It really didn't take long before I'd tagged thousands of tracks. I'm still barely a third of the way toward rating my entire library, but I'm already reaping huge rewards: There are times during a long ride when you want to be challenged with obscure tracks that shine a light on your preconceptions about art. But then there are those times when you just want to pump your fist in the air and yell, "She LOVES youuuu yeahhh, Yeahhh, YEAHH, YEAHHHHH!!!!"

You can't really make that happen without having some ratings in your library.

So honestly, I can't say that I've had any complaints whatsoever about the lack of a hard drive in my iPhone, or the lack of a card slot (which is something you find in most other smartphones). Even today, after the iPhone has become like the swine flu virus in terms of impact and global reach, there are still folks who complain that the iPhone has no card slot.

"Turn out your pockets," I said to one complainer, a Blackberry user who had really pushed me too far.

"What?"

"Right now. All of them. Let's see everything you have in your pockets. Because if the fact that the iPhone doesn't have a slot for an additional storage card really is a total deal-breaker for you, then you absolutely must be carrying more than 32 or 64 gigs' worth of memory cards on you. How I don't envy you, with an absolute need to have more than the massive amount of storage built into even the cheapest iPhone!

"And if you aren't carrying an iPhone's worth of memory cards," I finish with a condescending flourish, "then you're talking through your hat."

He wasn't carrying memory cards, thank heavens. If he was, I would have asked him if he truly preferred to swap out memory cards three times just to listen to Quadro-phenia all the way through.