Tweens went crazy over the musical made just for them. High School Musical products could reach $650 million in retail sales in the coming year. All High School Musical images © Disney.

The success of Disney Channel's High School Musical franchise has confirmed the power of tweens, a market that has been on the radar screens of the children's cable networks for at least five years.

The first High School Musical movie, which premiered in January 2006, has been seen by 250 million viewers worldwide, according to Disney, and the sequel by 69.4 million since its debut in August. Meanwhile, product sales have been robust: 7.5 million units of the original soundtrack and 3.9 million of the sequels; 8.2 million DVDs of the first film; and 9.3 million books, to name a few. Disney forecasts HSM products could reach $650 million in retail sales in the coming year.

"It made a huge impact because it was giving [tweens] something they never had -- a musical made just for them," says Adam Bonnett, SVP of original series for Disney Channel and Jetix. "It certainly raised the stakes for everybody, including us and our competition. It showed what an impact you can make."

Disney's competitors all agree that HSM hit on a formula that not only worked, but will have a lasting effect on tween programming. Above, a scene from the sequel High School Musical 2.

"For anyone in the children's space, High School Musical is going to affect everything, just as SpongeBob did," says Michael Ouweleen, Cartoon Network's SVP of development and current series. But he notes that Cartoon Network has no intention of creating a musical, and doesn't plan to move away from its core audience of kids 6-11. "It's more about how well they rolled it out," he says. "Tweens are a secondary part of our strategy. We don't focus on them, but we're happy to have them."

While the network hasn't developed any programming for tweens, it has acquired properties that appeal to tween boys, such as Naruto and other shows in the Toonami block. And its expansion into long-form and live-action programming also has resonated with tweens, although that hasn't been the intent. The network's new live-action show Out of Jimmy's Head, for example, attracts roughly the same number of tweens as it does 6-11 kids.

"[With HSM, Disney] had a formula that worked," says Marjorie Cohn, Nickelodeon's executive VP of development and original programming. "We never want to imitate that, because it wouldn't have the same impact. We want to put our own stamp on it." Nickelodeon's core demo also is 6-11. Tweens represent a significant part of that, according to Cohn, who notes that there is a big overlap between 9-14 tweens and kids 6-11.

The children's cable networks have been going after the tween market for years, to varying degrees. Disney Channel launched Lizzie McGuire in 2001. "We made the decision to target this demographic that was under-targeted at the time," Bonnett says. "That was the first scripted show that really had laser focus with this demographic." Other Disney Channel properties for tweens have included the Cheetah Girls franchise, The Suite Life of Zack & Cody, That's So Raven and the current sensation, Hannah Montana.