A lifetime of reading interviews with musicians leaves odd things stuck in your head. During the early '90s, when Details had some of the best music coverage to be found anywhere, I read a Q&A the magazine had done with Henry Rollins near the 1992 release of Rollins Band's The End of Silence, which is 72.5 minutes long—typical for the period. Rollins was asked about the album's length. His response—and this is from memory—was that all future Rollins Band albums would be 70 minutes or longer: Compact discs were expensive, after all, and Rollins didn't want to rip off his fans. I was in high school when I read this, and I thought it a rather noble gesture. Then the next Rollins Band album, Weight, came out in 1994, with a total running time of 53:26. Could you blame him for backsliding? Seventy minutes is a lot of music, especially if you're the one making it.

And Rollins wasn't the only one to turn down the extra running time offered by the CD. Let's look at some recent albums, shall we? Here's the strong self-titled debut from local power-pop singer-songwriter-drummer Michael Benjamin Lerner, aka Telekinesis. Total time: 31:38. Another Seattleite, Eric Elbogen, recently relocated from Brooklyn, operating as Say Hi: His latest is Oohs & Aahs, 31:25. I've heard nice things about Phoenix's Wolfgang Amadeus Phoenix; when I play it, I can do so assured that it will take just over 36 minutes of my time. JJ No. 2, ethereal Swedish indie-pop with a beach-baked feel that Pitchfork likes, takes even less: a head-spinning 26:43.

Obviously, this is a small sampling—but I think a telling one. The half-hour album was, in the '60s and even '70s, commonplace. It is again now, but for far different reasons.

Much has been said about the death of the album at the hands of the MP3. Certainly, pop music's center is no longer the album but the freestanding song, however many good or great albums may be released now or in the future. And there's been a seeming knock-on effect with albums themselves: They've been getting noticeably shorter for the last 10 years or so. That makes sense: The '00s have been the Incredible Shrinking Decade, from the reduction of newspaper and magazine word counts to digital media becoming more hand-holdable to the internet's reduction of any number of boundaries. Albums are now seemingly just as long as artists care to make them—a noticeable difference from the CD era, during which albums seemed to be as long as artists could make them.

A quick history: The long-playing microgroove 12-inch disc—the LP—was introduced in 1948 and by the mid-'50s was the medium of choice for adult music fans. Jazz, classical, Broadway, and pre-rock pop thrived on LP, while kids, particularly rock-and-roll fans, stuck to 7-inch 45 rpm singles. An LP could hold as much as a half-hour of music per side—a number of Bob Dylan albums came close—but most stuck to 15 to 22 minutes: shorter sides, better fidelity. The LP as concentrated artistic statement begins with Frank Sinatra's thematic '50s albums, but as rock and roll became art music as well as dance music in the mid-'60s, it too became identified with the LP, and expanded from a half hour, give or take, to an average of 35 to 45 minutes apiece.

The compact disc changed all this. The new format enticed fans to repurchase old favorites, as well as opening a previously untapped reissue market, but its effect on contemporary albums was bloat: Artists had up to 80 minutes of playback time, and they used it. Perfect example: In 1982, Michael Jackson edited down Thriller to 19 minutes a side (it was originally 26 minutes per) for maximum LP clarity; a decade later, he made Dangerous a CD-era-definitive 77 minutes. (About cassette tapes: Even during the cassette's halcyon era, the LP was still the measuring stick; "bonus tracks" existed on tape, but it was the CD that made them a staple.) By the late '90s, hour-long albums—something once almost unheard of unless you were releasing a double LP—were so standard they became blasé.

Around the first dot-com crash in 2001, pop music generally began to strip away its late-'90s excesses. Electroclash and '80s revivalism helped dance music move away from the whooshing superclub sound (evocative of jets taking flight—the moneyed good life), and "epic" track lengths began to scale back in turn. Hiphop and R&B beat-making was becoming more minimal, eventually giving rise to tracks that sounded almost tailor-made for cell-phone ring tones; the endless skits and interludes that larded rap records also began to scale back. The "rock is back" wave shunted Creed and Nickelback out of music magazines (if not actual rock-radio playlists) in favor of the wirier, dirtier-sounding Strokes and White Stripes. It doesn't seem like a coincidence that album lengths, too, began to tighten up.

Much as I'd love you to just take my word for it, though, I figure an assertion like this needs some data to back it up. What follows is far from complete and by no means scientific; nevertheless, I think it's indicative. Even before the digital era blew up the amount of available music to an unmanageable degree, the record business offered more than even a fanatic could keep up with; there's no way to calculate the industry's total output, especially now. So to keep things simple, I used data from AcclaimedMusic.net, which processes hundreds of year-end and all-time lists into überlists of the most critically adored albums and singles of the rock era. Beginning with 2008 (too soon for '09), I calculated the mean length of Acclaimed's top 10 albums every five years going back to 1978; vinyl LP lengths stayed consistent for so long that going back further seemed beside the point. Here are the results, with artists in parentheses:

1978: 40:54 (Elvis Costello, Bruce Springsteen, Blondie, the Jam, Pere Ubu, Funkadelic, Van Halen, Kraftwerk, Talking Heads, Big Star)

1983: 41:03 (R.E.M., Tom Waits, the Police, U2, New Order, Def Leppard, Metallica, Minor Threat, ZZ Top, Aztec Camera)

1988: 46:18 (Public Enemy, Sonic Youth, Pixies, N.W.A., Jane's Addiction, Talk Talk, Tracy Chapman, R.E.M., Leonard Cohen, My Bloody Valentine)

1993: 50:12 (Nirvana, Björk, Smashing Pumpkins, Wu-Tang Clan, Liz Phair, PJ Harvey, Suede, Breeders, Underworld, Afghan Whigs)

1998: 57:00 (Air, Lauryn Hill, Lucinda Williams, Mercury Rev, Massive Attack, Fatboy Slim, Neutral Milk Hotel, Madonna, OutKast, Manu Chao)

2003: 57:05/51:54 (White Stripes, OutKast, Dizzee Rascal, Radiohead, the Shins, Blur, Darkness, Mars Volta, Cat Power, the Strokes)

2008: 44:29 (Portishead, Fleet Foxes, TV on the Radio, Vampire Weekend, Bon Iver, MGMT, Nick Cave, Deerhunter, Santigold, Elbow)

Obviously, there are plenty of variables: These lists fail to account for any number of genres, trends, movements, and styles. There are variables within the lists as well: Funkadelic's 1978 One Nation Under a Groove is a 59-minute LP plus bonus EP, OutKast's 2003 double CD is by far the longest item on any list (the two '03 numbers are the mean per title and per disc, respectively), and I eliminated Bob Dylan's Live 1966 on the grounds that it wasn't a real 1998 album.

Nevertheless, the results speak for themselves. The hour-long album hasn't vanished, but there are a lot fewer of them than there used to be: Half the '98 albums are over 60 minutes, while the '08 list features only one (Elbow) that even approaches an hour (58:30). The music biz may not be able to save itself from irrelevance in the digital age, but at least it's a little less demanding of your time.