It's hard to imagine that the producers of "American Idol" would want to tinker with the show's formula following last season. After all, the hit reality program -- a talent search for music's Next Big Thing -- was 2006's top-rated TV series by a wide margin. But when the "A.I." juggernaut returns for its sixth season Jan. 16, that's just what they'll be doing.

In the biggest tweak of the show in years, a new national songwriting contest will be introduced and run parallel alongside the usual singing competition. The winning song, as determined by viewers, will serve as the first single from the champion of "Idol."

It's fine-tuning like that -- a quintessential "Idol" touch -- that has enabled the franchise to maintain its steady upward trajectory during its five-year run.

Last season was the show's biggest and best yet. According to Nielsen Media Research, the show averaged more than 30 million viewers -- ratings that trail only the likes of special one-off events like the Super Bowl and the Academy Awards. What is more, Ad Age says the show generated more than $500 million in TV sponsorship revenue in 2006. It now sets the value of the "Idol" franchise at $2.5 billion. A record four contestants were signed to album deals with Simon Fuller's record company, 19 Entertainment: Taylor Hicks, runner-up Katharine McPhee and finalists Chris Daughtry and Kelly Pickler.

Now the franchise -- which through the years has given rise to the platinum-selling careers of Kelly Clarkson, Carrie Underwood, Clay Aiken, Ruben Studdard and Fantasia Barrino -- is thinking even bigger as it heads into its latest season.

Says a relaxed and confident Fuller, "Idol" creator and mastermind, "We're just hitting our stride." So what can viewers, not to mention advertisers, expect in the season ahead?

Click here to read the entire article, including the keys to the franchise's ongoing success, tweaks to this year's show and the latest on celebrity judges and guest performers, and more.