Like millions of American teen-agers, Sasha Eckstein has figured out that she doesn't need to spend $20 on a band's CD just to hear its one hit song.
"Generally, if I like a song I hear on the radio," said Eckstein, a high school sophomore, "I'll wait and see if it shows up on one of the compilations."
Chances are that it will, usually on the Now collection.
Four weeks ago, the best-selling album in the United States was Now 9, a compilation of 20 recent Top 10 hip-hop, rock and pop hits by different artists.
According to SoundScan, more than 420,000 consumers bought Now 9 the week it was released, easily outselling The Best of Both Worlds, a much-hyped Jay-Z/R. Kelly collaboration, which sold 223,000 copies its first week.
The Now concept has been around since the mid-1980s, but only overseas. (Now 52 a double-CD of 43 songs, recently was released in Europe.) The first U.S. version wasn't released until late 1998. Since then, eight other Now collections have been released in the United States, and each has been a commercial success: The nine installments together have sold more than 24 million copies, according to SoundScan.
The success of these and other compilations, music industry analysts say, reflects a change at record labels and among performers and young consumers. And it portends the end of one of the recording industry's pioneer formats, the single.
For their most loyal customers - usually teens - the Now compilations have become the economical way to buy a lot of hit singles in one swoop.
"I've bought three [NowCDs]," said eighth-grader Kayla Guetlich. "Kids buy them because you can get a lot of songs that are real popular without having to spend money on a bunch of CDs."
That was one reason record companies resisted releasing hit collections in the United States: They figured album sales would suffer. Another reason: Previous compilations had failed commercially.
"The guy who changed things was Ray Cooper of Virgin Records, a big proponent of hits compilations," said Geoff Mayfield, director of charts for Billboard magazine. "He came over from the U.K. and became a cheerleader for them in America."
The Now collections are released collaboratively by four of the five major record conglomerates. The first featured several fads (Cherry Poppin' Daddies, Hanson) and one-hit bands (Harvey Danger, Fastball).
But two things separated even the first Now from the cheesy, K-Tel, one-hit-wonder collections of the '70s: Several artists were red-hot stars such as the Backstreet Boys and Janet Jackson, and none of the songs was more than a year old.
Indeed, Now itself became a bona-fide brand name, like MTV's TRL or BET's 106 & Park. Once that happened, the compilations started getting even more star-studded: U2, Aerosmith, Incubus, Jennifer Lopez, Mary J. Blige, Aaliyah and - most crucially - the Backstreet Boys, 'N Sync and Britney Spears.
Each Now collection is separated into three distinct genres: The first five or six songs are pop songs; the next five or six are R&B or hip-hop tunes; and the rest are rock songs.
Those who watch record-sales charts say there's only slight evidence that the Now compilations have hurt their artists' record sales.
"It's not unusual to see a dip in sales for albums that have contributed to a new Now compilation," Mayfield said, "because there's less urgency to get that album for that song. But that dip usually lasts no more than a week or two."
What's more likely is that Now and its more occasional brethren - like the Totally Hits collections - have cut into sales of CD singles, which have plummeted the last two years. Total sales were down 41 percent in 2001 (to 30 million from 51 million); sales this year are down again by a whopping 67 percent.
"Why spend $3.99 for one song and maybe a couple of remixed versions of that song when you can get an entire album of hits for $10 more?" Mayfield said.
For record historians, the sales decline and all this repackaging is another sure sign that one of the earliest forms of recorded music - the single - is nearing complete demise.
Part of that is due to the cost to consumers; part is due to technology - CD players aren't made for singles like the old hi-fi systems were; part is due to compilations and soundtracks, which are now omnibus collections of radio hits.
"The very term `album' comes from the old 78s, which were actually singles packaged in booklike compilations that looked like photo albums," said Scott O'Kelly, an archivist at the Marr Sound Archives and a record enthusiast.
"I'm a dinosaur when it comes to listening to music, but there was a whole different charm to [singles]. There's nothing like that these days.
"I was spinning 45s at a party recently and these young kids came up and one pointed at the records and said, `There's one.' They were kind of amazed that there was music on both sides."
There's some evidence that the Now collections are starting to lose some commercial steam. First-week sales for Now 9 were down from Now 8 (549,000), which was down from Now 7 (621,000). Still, after three weeks, Now 9 was well beyond certified platinum - 1.3 million sold - and not the only successful compilation high on the charts.
That same week, Forcible Entry, a heavy-rock compilation produced for the World Wrestling Federation, was No. 11 on the Billboard Top 200 chart, down from No. 3 the previous week; and Totally Country, the Nashville version of Totally Hits, was No. 4 on the country charts for the second week in a row.