How much will Paula's departure cost 'American Idol'?

Paula Abdul was the heart of American Idol. Last night she Twittered that she had quit the show. And now Idol producers -- Fox Broadcasting, Fremantle Media and 19 Entertainment -- are left wondering whether they made the right move in letting her go to save a few million dollars in salary and end the drama she generated. The answer boils down to whether an Idol without Paula loses so many viewers that advertising revenues plunge.

Let's review the facts. Idol has been the highest rated program for years, but its numbers have dropped -- for example in the 2009 premier, Idol attracted 30.074 million viewers -- 10 percent fewer than in 2008. Idol charges $500,000 per 30-second advertisement -- rising to $600,000 per half-minute for the finale. Abdul had been making $2 million a year and the producers offered her a $10 million multi-year contract, which somehow amounted to a 30 percent raise. This was less than she believed she was worth to the show.