The Daily News reports that ratings for Walt Disney Company (NYSE: DIS) Hannah Montana program are down 24% since Mileygate broke last week. Last Sunday's new episode's ratings fell 24% from the previous fresh episode, which aired just under two months earlier. And ratings are down 33% since the first episode in January.

Disney thinks everything's fine with Miley. The Daily News quotes CEO Bob Iger as saying: "With a new season of shows coming up, a new record in July and a theatrical film next year, the 'Hannah Montana'/Miley Cyrus franchise is incredibly robust." But kid franchises such as "Hannah" that peak at very high levels are good for roughly 18 months, then start to fade.

Will this have any effect on the $1 billion business that is Miley Cyrus? It depends on whether she can find a new -- older -- audience and deliver what it wants as effectively as she did for the 10 to 14 set. If Mileygate helps her do that then her business will be fine.

Peter Cohan is President of Peter S. Cohan & Associates. He also teaches management at Babson College and edits The Cohan Letter. He has no financial interest in Disney securities.