It's Tuesday. Album release day. A day that has historically brought much hullabaloo to many a record store. But as rain taps on the windows of Olsson's Books and Records in Bethesda -- it is, indeed, a beautiful day to nose around for an album -- there is not even a whisper in the CD aisles.

"Nobody even knows that Tuesday is album release day anymore," said Lucas Hayes, a music manager at the store, standing next to a promotional billboard for Ry Cooder's new album. "Sometimes I have to explain that to people."

There are now dozens of ways and dozens of places to buy music, nearly all of which involve clicking a mouse, not lining up at a record store. The main variable in waiting times is not the band, but bandwidth.

Nearly 140 million individual songs were (legally) purchased online last year, which is up from somewhere close to zero the year before, according to the Recording Industry Association of America. Purchases of single-track CDs were 3.1 million, down from 8.3 million the year before and 34.2 million at the start of the current millennium.

This year, one in five music buyers ages 12-21 bought music online, and one in three reported buying fewer CDs because they can procure just about anything they want online, according to a forthcoming survey by Forrester Research.

Music companies have had to move quickly to adapt, marketing songs and albums to subscription sites, Internet radio and even cell phones. However, wherever, whenever music can be played, record companies have pounced to get there. Warner Brothers last week announced the debut of a band on every format except CD; Sony is struggling to establish an online music store. Companies are even trying new CD technology that combines music, data (such as lyrics) and video on two-sided discs.

The choices and technologies in music-buying bring to mind the old saying about computers: As soon as you take one out of the box, it's obsolete. In the case of music, as soon as you decide how to purchase tunes, a new way (or technology) comes along.

"It's all very complicated, which is just crazy," said Ted Schadler, a music industry analyst for Forrester Research. "Unless you're a music lover, maybe you don't bother with it. It's hard to find your way around."

There's Apple's iTunes, for starters. Something called Rhapsody, which sells monthly subscriptions to music. Yahoo sells its version. Napster used to traffic in "shared" music; now it charges. There's That's for independent labels. AOL sells tunes. Wal-Mart, too. And on and on.

Many music fans find all the choices exhilarating. Many more find it a dizzying mess.

For instance, when is a song good enough to warrant actually buying an album? Once that particular mystery is solved, do you buy the album online, through iTunes? Or make a trip to Olsson's? If so, do you then upload the CD to your hard drive for use with an iPod or other MP3 device?

The questions pile up like bad B-sides.

So Hayes, 26, has decided to dodge the digital music world altogether. He owns about 1,500 CDs. The CDs exist not in bytes, but in stacks -- lots and lots of stacks. He has downloaded few, if any, songs from the Internet. When he wants to buy an album, he uses his employee discount.

But he's learned a thing or two about how some people decide to buy music in what form.

For instance, people into classical music or jazz almost always buy actual CDs. That's because they are interested in the music's subtleties -- the highs of a saxophone, the lows of a bass drum -- that can be affected by the way digital files are created and compressed.

When it comes to rock music, he's found that the decision to buy a CD is often directly related to the band at hand. A Britney Spears album is generally not designed to be listened to in the same manner as a Radiohead album, which is to say as a collection of songs, a series of moments that add up to an experience, maybe even an epiphany.

The evidence:

"Oops! . . . I did it again. I played with your heart, got lost in the game," according to Spears.

Radiohead: "I call up my friend, the good angel/But she's out with her ansaphone/She says she would love to come help but/The sea would electrocute us all."

Hayes has also noticed that many music shoppers have a particular affinity for the $8.99 bin -- not for the price, though that's important, but for its contents. He points out an old Ry Cooder album. There's Billie Holiday. There's a remastered version of "Ocean Rain," released by Echo and the Bunnymen way back in time, in 1984.

"That's a classic album that everyone should own," Hayes said.

A classic album. That very description has gone classic, too.

Christine Chang listens to samples at a record store in Berkeley, Calif., as more people buy music online.