NEW YORK — For the editors, it was a simple matter of covering costs. But for those who spent their youths praying at the shrine of Alfred E. Neuman, it was unforgivable.

Yes, Mad magazine has finally started taking ads. After holding out for nearly 50 years, the caretakers of this American humor institution have finally buckled, citing the need for more revenue to cover a long-awaited switch to full-color publication.

What's that? Some of you didn't even know Mad magazine was still on the newsstands? Not only is it still around, but there are still plenty of people who care enough to sound off about this perceived sellout by Mad, once considered an edgy, even subversive magazine in its heyday.

"It's a shame — it's the end of an era," lamented Michael Gallagher, a comic collector and vendor in New York. "I'm really surprised. But hey, everyone's doing it. Mad used to be cool and hip, but now they're going mainstream."

"Mad certainly is not what it used to be," said Roger Williams, another comics store owner. "Once it was something you'd read under the covers with a flashlight for fear of your parents catching you, but now it's pretty G-rated."

In a note at the beginning of the March issue, the editors broke the news to their readers with a generous dose of irony. "We offer two exciting new concepts that are sure to revolutionize the magazine business: color and advertising."

John Ficarra, co-editor of the magazine, is sure that the griping will pass. And besides, in order to finance the switch to full color, they'd either have to take ads or drastically raise their cover price, which at $2.99 is still touted as "Cheap!"

"Some people will never accept change," Ficarra said. "It's the same magazine it always was, except now we'll have a better-looking magazine . . . The world was in full-blazing color and Mad was still coming out on newsprint."

Mad refused ads for decades at the insistence of its founder, the iconoclastic William Gaines. From its old perch on MADison Avenue, a building Gaines expressly chose because it had a 13th floor, the magazine spent decades thumbing its nose at American companies and pop culture.

But with advertisements now appearing everywhere — from beer glasses to movie theaters — Mad's editors figured that few would be shocked to see them alongside "Spy vs. Spy," "A Mad Look At . . . " and the magazine's other fixtures.

Besides, it's pretty clear that they could use the money. Mad won't disclose any financial data, but its circulation has declining sharply since the early 1970s, when it hit a peak of 2.3 million, and currently stands around 250,000. Mad is now owned by a division of AOL Time Warner Inc.

Still, Maria Reidelbach, an author and artist who wrote a history of the magazine, dismisses the notion that Mad is past its prime, saying that nostalgia for the Mad of old could just be readers longing for their lost youth.