I can't get enough of VH1 Classic, a music channel buried so deep on my digital cable lineup (Channel 473) that I'm amazed I ever noticed it. But I did, and late at night, while reading a book or magazine, I often turn it on for background ambience.

The channel's charm is that it goes deep into an artist's catalog and frequently plays a video I haven't seen in more than 20 years. Often, I've never seen the video, but the song brings back memories. It's a new discovery of sorts.

Two examples from a recent evening include China Crisis' "Arizona Sky" and a great Smiths tune, "There is a Light that Never Goes Out." (And if a 10-ton truck/Kills the both of us/To die by your side/Well, the pleasure, the privilege is mine.)

Those morbidly romantic lyrics made me laugh all over again and brought back memories of college, when I'd sit around with friends, drop a needle on the vinyl and swap music.

Well, life goes on, and who has time for that anymore, let alone a turntable. But we still want new music, new recommendations and new memories.

Over the past month, several people have mentioned how they have become ardent fans of Last.fm, a social-networking site geared toward music discovery. I've been listening and like what I hear.

It's a great example of how social networks are shaping our tastes, where a word-of-mouth recommendation is no longer singular but rather a group effort.

"We wanted to replicate the word-of-mouth model," said Martin Stiksel, who co-founded the site with two others in 2003. "You have a network of friends that plays music you like. You share their interests, and that's essentially what Last.fm does."

As social networking exploded into the public consciousness last year, so has Last.fm. It is based in London, but before the recent holiday season it launched sites in a dozen other languages, including Polish, French and Russian. Now it's a global phenomenon for music fans, with more than 15 million active users each month.

"We started with two thoughts," Stiksel said. "How do I find music that's interesting to me? And how do I promote this to the right people?"

Hence, in the same year MySpace.com was born, Stiksel (originally from Austria), Felix Miller (Germany) and Richard Jones (England) began building a social network focused around music.

If you have been reluctant to try a social network but can't leave home without your iPod, Last.fm is a good place to start. (The .fm may sound musical, but it's not for frequency modulation. Last.fm is registered in the Federated States of Micronesia, and for about $15 a month you also can get a .fm domain.)

To get started, just go to Last.fm and look around. I was prompted to type in a favorite band and entered the Shins, whose new album I'm eagerly awaiting to hear. No luck, it wasn't available for a listen. Instead, Last.fm created a guest playlist based on bands similar to the Shins. Five of the six bands included to illustrate the type of music I would hear were from groups I liked.

Intrigued, I registered for the site, which is free and only took minutes. Shortly after, I created my own radio station by adding the names of bands or artists I like. Here's what I popped in: The Decemberists, The Shins, John Coltrane, Miles Davis, Electric Light Orchestra, The Smiths, Abba (who doesn't like "Dancing Queen"?), Eminem, AC/DC, Common, Echo & the Bunnymen and Fatboy Slim.

Seconds later, my station started, and the first song was from Sufjan Stevens, whose "Illinois" CD was a favorite last year. Then a Beatles song popped up ("Roll Over Beethoven") and then the Shins' "New Slang," a great tune. And on and on, including an awful Abba song ("One Man, One Woman"), but I only have myself to blame for that.

I liked roughly 90 percent of what I heard on my own radio station, and much was music I had never heard. And similar to VH1 Classic, my radio station went deep into an artist's catalog, playing, for example, a live rendition of ELO's "Whisper in the Night," a version I never heard.

You can buy the music, too, if you like what you hear. The site includes links to online retailers like Amazon.com to purchase CDs. In the UK, you can buy MP3 downloads, something Stiksel said he hopes soon will be available in the U.S.

In addition, more than 100,000 tracks are available for free download on the site, mostly from undiscovered talent looking for exposure. Those tracks also are recommended based on your preferences. I didn't download any of those tunes, but I listened to quite a few that I liked.

Another bonus: Those free MP3s are unprotected files, meaning they will play on any digital music player you have, including an iPod, a Zune or a SanDisk Sansa.

You also can see (and hear, of course) what your friends or "neighbors" - what Last.fm calls the people with similar tastes to you - are interested in. Stiksel said checking out what your friends play is the most popular thing to do on the site.

Then you send them a note "and slag them because they're listening to some rubbish," he said, laughing.

Which is not much different from when your college buddies gave you grief after finding that Abba stash among your vinyl.