Just like its kids-only audience, Nickelodeon has grown a lot since the cable network's austere premiere 11 years ago.

Back then, an un-hip mime was the commercial-less channel's logo. Today, reaching into 52 million households, Nickelodeon is known by its trademark orange wiggly blob that transforms into different shapes, from a dog bone to a royal castle.Barbara Bush and New Kids on the Block do public service announcements for Nickelodeon.

Singer Tom Chapin performs a tune with the household hook, "In the nick of time, that's when kids arrive."

Pee-wee Herman, who has his own show on another network, drops in for some Q & A.

Obviously, Nickelodeon exercises its leadership muscle. With more youngsters viewing more kid shows on Nickelodeon than on ABC, CBS and NBC combined, that's clout.

And commercial power, from Colgate Junior toothpaste to Barbie dolls driving '57 Chevys, Nickelodeon pitches products to little consumers who inhabit what the network calls "kid-dom."

Since 1984, Nickelodeon has targeted youngsters with ads and shows that look just like children's television on the other networks.

But there's also green slime dumped on whoever is in range and a Mister Rogers-type, Fred Penner, who lives in a tree stump. What makes Nickelodeon distinctive is that it's in sync with the sense of humor of kids. And the joke is often: Yes, your parents are as un-cool as you think they are.

A recent Halloween promo urged kids to tell their parents to stay away from the telephone because Nickelodeon was going to call.

In a recent interview from network headquarters in New York, Nickelodeon president Geraldine Laybourne concedes parents just tuning in the segment probably wouldn't get the inside nature of the jesting.

"It's a joke between us and our audience," says the 43-year-old executive, who, after earning a master's degree in elementary education at the University of Pennsylvania, co-founded the Media Center for Children in New York.

"It's hard to explain. But I will say that adults like us because after kids watch Nickelodeon, they're not bratty. They're feeling good, with a sense of power."

Jack Levine, head of the advocacy group Florida Center for Children & Youth in Tallahassee, agrees. His children, ages 5 and 9, love Nickelodeon as much as he does, he says: "I see a lot of active cleverness on that channel. As far as the kids-only attitude goes, I don't see it as offensive."

Nickelodeon also is packaged for short attention spans, patterned after the staccato style of the granddaddy of video babysitting, 21-year-old "Sesame Street." But Nickelodeon places an unabashed emphasis on entertainment rather than education.

Peggy Charren, the founder of Action for Children's Television, a Boston-based advocacy group, has been critical of Nickelodeon. She recently was quoted as saying, "If there's a problem with Nickelodeon, it's that maybe they don't take seriously a kid's need to know."

But Nickelodeon's Ms. Laybourne says now that Nickelodeon has kids' attention, it's time to change that all-play image.

"I'm not saying that five years from now kids will come home from school and see a history lesson on Nickelodeon," she says. "But we are definitely shifting toward more information."

Ms. Laybourne says a group of the nation's educators recently were invited to New York for a think-tank day.

In the works is a news show, but Ms. Laybourne admits she's nervous about this effort. "We think we know what we want to do," she says. "But unlike game shows, if we blow this initial project, I'm afraid we'll ruin a whole genre." So she says Nickelodeon will tinker some more with a headline format featuring stories with a heavier dose of background than adult newscasts.

As education moves to the forefront of Nickelodeon, though, don't expect the high jinks to go away