I’m having trouble thinking of any industry that has faced more tumult since the arrival of the Internet than the music business.

From Napster to the iPod to Zune, and downloads of singles to cellphones, the music labels have had to try to constantly adapt to an ever-changing consumer landscape.

It’s no surprise, then, that three of the four major U.S. music magazines saw a sharp drop in advertising revenue in Q-1 this year. The granddaddy of them all, Rolling Stone, took the biggest hit of all — a whopping 33 percent drop in ad pages plus a 27 percent loss in revenue, according to the Publishers Information Bureau.

Advertisers are increasingly seeking new markets beyond print magazines to reach their customers. “We’re putting money in Pandora and other music [sites] that in the olden days would probably all have gone to Rolling Stone,” Scott Daly, executive media director at advertising agency Dentsu America, told analyst Matthew Flamm at Crain’s. “We’re trying to reach young, early adopters…”

So, can Rolling Stone adapt to the new landscape? After all, it’s defined music publishing for 40 years; Jann Wenner, it’s founder, editor, and (along with his ex-wife Jane) owner, turned 62 in January, and thus is among the first wave of Baby Boomers expected to slow down, at least, if not retire in the coming decade.

Insiders say Wenner almost sold the magazine in the past, when the business was sliding, but if there are any rumors of that sort lately, they haven’t reached us yet. The property still is huge for a niche magazine, with over $31 million in ad revenue in Q-1, but… compare that with over $42 million in Q-1 ‘07, and you see dangers facing Wenner as he captains his flagship into its fifth decade.

It has been a long, strange trip, indeed, but it’s likely to get a lot stranger in the Digital Decade to come.

(Note: I wrote and edited for Rolling Stone from 1974-’77, and have been working on a memoir of that period)