NEW YORK (CNNMoney.com) – The tortured strains of tone-deaf "singers" convinced that they are the next Mariah or Usher is sweet music to the millions of fans of Fox's hit show "American Idol."

The off-key warbling is even more soothing to executives at Fox and its parent company, media giant News Corp. (Research) "American Idol," the most-watched show during the 2004-2005 season, returns to the prime time lineup on Jan. 17 and it's not a moment too soon for Fox.

Nearly 27.5 million people, on average, watched American Idol's Tuesday episodes last season while 25 million viewed the Wednesday recap and results show.

Fox is currently trailing CBS, ABC and NBC in the 2005-2006 ratings race. But thanks to the upcoming return of "American Idol", the network could quickly catch up.

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The network is currently in fourth place in the ratings race, according to Nielsen Media Research. But that's familiar territory for Fox.

Fox struggled during the beginning of the 2004-2005 season but the success of "Idol" helped lead the network to its first ever full-season ratings victory in the battle for 18 to 49 year olds, the demographic that is most sought after by advertisers.

The show has generated big bucks for Fox. Media buyers said that Fox has been able to charge advertisers more than $700,000 for thirty-second spots on the Wednesday results show, tops for a regularly scheduled prime time show. ("American Idol" typically airs episodes on Tuesday and Wednesday nights.)

Fox has also attracted lucrative sponsorship deals from the likes of Coca Cola, Ford and Cingular Wireless. A spokesperson for Fox confirmed that these sponsors have all signed on for this season as well.

But now that "Idol" is heading into its fifth year, can it continue to remain on top of the ratings heap? After all, many reality shows have tended to wear out their welcome with viewers quite quickly. ("The Apprentice" and "The Bachelor," anyone?)

In addition, there was a bit of controversy surrounding the show last season. A former contestant alleged that he had an affair with "Idol" judge Paula Abdul, sparking concerns about the integrity of the show's results.

Still, several TV industry experts said they don't expect any "Idol" backlash.

"Shows like this have a certain shelf life and the spiral tends to be rather quick and dramatic, but I don't think anyone expects this to be the year when 'American Idol' jumps the shark," said Kris Magel, senior vice president and national broadcast account director with ZenithOptimedia, a media buying firm.

Andrew Donchin, director of national broadcast at Carat USA, another media buying firm, added that Fox wisely decided to run the show only from January through May instead of having two contests per season.

That's in stark contrast to what NBC has done with the Donald Trump version of "The Apprentice" and how ABC burned out viewers back in 1999 by running its "Who Wants to be a Millionaire" game show almost every night of the week.

"I admire what Fox is doing. Fox is selective, only running it once a year. That whets people's appetites for it," Donchin said. "It's the opposite of the Millionaire fiasco."

Still, Donchin said that the general decline in TV viewership may hurt "Idol" too. But even if ratings dip a bit, another media buyer said that shouldn't be a major cause for concern.

"'Idol' is to prime time what the NFL is to sports. Even if it slightly erodes, it's still a remarkably powerful franchise," said John Rash, senior vice president and director of broadcast negotiations with Campbell Mithun, a Minneapolis-based ad agency owned by Interpublic Group.

And this year, "American Idol" could wind up generating even more revenue for its parent company if Fox decides to feature "Idol"-related content on its social networking site, MySpace.com, which News Corp. acquired last year to take advantage of booming demand for online advertising.

MySpace is immensely popular with many of the younger viewers that "American Idol" has tended to attract. According to data from Web tracking firm Nielsen//NetRatings, MySpace had 24.5 million unique visitors in November, a traffic increase of more than 750 percent from a year earlier. What's more, the site has a particularly heavy focus on music.

So it would seem to be a natural extension for Fox to try and cross-promote "American Idol" heavily on MySpace, especially towards the end of the show's season when the finalists emerge.

Given the show's immense ratings success, content about the show (i.e. contestant profiles, online chats about the show and unaired song and video clips) would seem likely to generate strong online advertising opportunities for News Corp.

The Fox spokesperson would not comment on plans to feature "American Idol" content on MySpace.

But News Corp. chairman and CEO Rupert Murdoch, speaking at Citigroup's annual global entertainment, media and telecommunications conference in Phoenix Monday, said that the company had big plans for MySpace, including the recent launch of free video downloads, its own instant messaging services and eventually, an Internet phone offering.

For a look at how News Corp. rival Disney is embracing digital technologies, click here.

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