Last year I received an iPod Nano for Christmas, and with help from my brother, I loaded it up with some tunes by my favorite artists. In my world, Johnny Cash and Joan Armatrading are two of the most amazing musicians ever to have existed, but after spending the ski season on Mad River Glen's single-chair lift listening to the same 20 or so songs, I'd had enough. I stuck my iPod on a bookshelf and forgot about it.

Then a friend told me about his college-age son's immense iTunes library. I decided to give my player another chance, and asked the son, who is 17 years my junior, to show me the ropes. A handsome, bespectacled kid in his sophomore year at Bates, he showed me how to plug my device into his computer, browse his full, unedited iTunes library and, with a simple drag of the mouse, copy anything I wanted directly onto my iPod. Within an hour, I had fortified my player with more than 500 songs.

I'd offered to pay my teacher for his consultation, but he quickly assured me that no remuneration was required.

But didn't it cost him money to purchase all those songs? I wondered.

Apparently not. Everyone at his school shares music on an open, campus-wide network, with no money involved, he explained.

As I thanked my young consultant, he gently suggested that I get some music from other sources besides him. "You probably don't want to be listening to my music all the time," he said.

"Sure," I replied, brushing off his words. Whatever.

But that afternoon, I began to understand his concern. As I started to explore my new music, I realized that I was getting to know this kid perhaps more intimately than he'd intended.

I listened to "Lynguistics" by a group called Cunninglynguists. I couldn't even bring myself to say the band's name out loud - it was too similar to a word I had spent most of my life trying to avoid.

I floated through the soundtrack to the movie Garden State. Oh, my gosh. This music was really, well, sensual. The thought of my iPod consultant experiencing it in the privacy of his dorm room made me uncomfortable. I shouldn't even be thinking like this, I scolded myself.

Then I began to wonder. Our society is swarming with people who walk around with little white earplugs in their ears. What are they listening to? Where do they get their material? And how does the music they listen to and share affect their lives outside the headphones?

People are identified by their musical choices," author Steven Levy observes in his book The Perfect Thing: How the iPod Shuffles Commerce, Culture, and Coolness. "They are judged and make judgments about others based on their music." He observes that iPod users often edit their music choices because of how they'll be viewed by their peers.

Adam, a senior at Harwood Union High School in Duxbury, describes a person's taste in music as "kind of like a belief." So what does he believe in? His iPod is loaded with KRS1 and Public Enemy and other hip-hop bands.

If people's musical collections are expressions of who they are, then sharing that music with friends helps them communicate who they are - or would like to be. Jessica, a University of Vermont senior with long, light-brown dreadlocks, sees her iPod as a way to connect with other people. Her library, taken from her own collection and those of her friends, includes Fiona Apple, rap, bluegrass and reggae bands such as Umphrey's McGee. She listens to it on her way to class, and when she's running.

"When I get some new music from a friend, it makes me want to go for a run so I can listen to it," she says. "Music can tell a lot about someone - it's a way to get to know them better."

Brian, a 28-year-old MBA student at Boston University, listens to a composite of music from five or six friends. Their choices say a lot about them, he suggests. "Pete still has a bunch of Van Halen on his iTunes," he says. "Van Halen is a reminder that even though Pete is cool now, he was dorky once. Haley's music collection was filled with so many sick, deep tracks, I was initially intimidated," he continues. "It told me that she was a thoughtful, troubled, cool woman."

Christina, a public relations specialist for Beaver Creek Resorts in Colorado, is more interested in connecting with her music-sharing friends than in judging them. "Certain music makes me think of certain people," she says. "Whether I like the music or not, I feel a bit closer to that person, having listened to his or her music."

Jake also sees music sharing as an important social interaction. "It's like sharing your history with someone," says the UVM freshman. "If you connect with someone's music, it's an instant friendship."

He downloaded most of the 120 or so hip-hop songs on his iPod from limewire.com, which allows users to share tunes for free. The website is very popular, but is it legit?

Don Mayer, founder of Small Dog Electronics, an Apple Computer reseller in Waitsfield and South Burlington, says no. Downloading someone's personal music collection onto your own iPod - whether through a site such as limewire or directly from another computer, as I did, is completely illegal.

"I don't see it as any different from stealing software," says Mayer. "Both limewire and Napster, which started out as computer-to-computer networking, are basically stealing from the artists."

Not all instances of downloading are verboten, though. In some cases, artists not only permit but encourage the practice as a way to market their product. Ed Shepard, who works at Small Dog, points to the example of Neil Young's latest CD, Living With War.

"Young provided the music on the web, in an inferior sound quality, a week prior to the CD's on-sale date, so fans could sample the music and get excited about it," Shepard relates.

File sharing can also turn fans into grassroots music marketers who expose their friends to music they might never have found on their own. Emma, a staff member in UVM's archaeology program, has discovered lots of new musicians through her friends' collections. Her colleague Matt, for example, who spent five years in the Caribbean, has introduced her to reggae musicians such as Damian "Junior Gong" Marley, a son of reggae legend Bob Marley.

Anitra, who also works in archaeology, adds that her friend Joe's musical taste "makes him quirkier to me. Being exposed to his music has led me to see live music shows in Burlington I probably wouldn't have gone to."

When Mayer helps customers purchase iPods, he advises them first to convert their CD collection to MP3 files and load them onto their iPod. And then, he says, "I talk to them about [Apple's] iTunes music store, because they have the most comprehensive music collection." The iTunes music store sells most songs for 99 cents apiece, and also offers free iPod contents.

For all their warnings against piracy, Mayer and Shepard both admit that the practice is rampant. And it's not just teenagers who do it. "In a recent interview," says Shepard, "Time-Warner Music's CEO admitted to having 'tons of pirated music' on his iPod."

The prevalence of pirating makes some users hesitant to purchase. David, a Harwood Union 12th-grader, says he won't pay for the rap, hip-hop and other so-called mainstream music he listens to because so much is available for free. He uses limewire.com and isohunt.com to download his collection.

But not everyone is convinced by that argument. David's classmate Patrick, a fan of underground heavy metal, doesn't believe in taking tunes for free. "I have a moral problem with downloading music because the bands don't get the money," he says. "These bands are trying to make it, and they need the money." Patrick uses soulseek.com to sample tracks. If he likes what he hears, he buys the CD. He only resorts to free downloading when he can't locate the disc.

These high schoolers tend to agree that established musicians such as rapper 50 Cent aren't likely to suffer from downloading, but emerging bands are. On the other hand, they point out that downloading music has allowed lots of bands to build fan bases and sometimes be discovered by big music companies.

Sharing files may be illegal and immoral, but it also makes the solitary practice of tuning into your headphones a social act. And just as it can make relationships, it can also break them. As one iPod user reveals, the discovery of multiple Britney Spears tracks on a potential mate's iPod library "put the kibosh" on future dating.