When U.S. radio giant Clear Channel Communications Inc. shortened its commercial breaks in 2004 in a bid to raise ad rates and lure audiences back from the Internet, iPods and satellite radio, the idea was dubbed Less is More. As in, fewer ads sold to a bigger audience at a higher price equals more commercial revenue.

But after compiling two years of data on ad sales and listener habits, the company has decided to rework that math. It seems that at certain times of the day, more is indeed more.

Next week, the operator of more than 1,100 radio stations will introduce its revised strategy that will see additional ad slots inserted at peak listening hours and into its most popular shows, including that of its marquee political commentator, Rush Limbaugh, above. Major events such as the 2008 U.S. presidential election and the Boston Marathon will also get the more-is-more treatment.

Meanwhile, commercial time will be culled significantly in off-peak times, such as overnight programming. While this idea isn't new to radio, Clear Channel expects to stretch the limits of the binge-and-purge approach to inventory management more than traditional radio has done in the past.

The Less is More strategy was credited with bumping ad revenue 6 per cent two years ago, but sales have since fallen, dropping 4 per cent last quarter. And having just signed Mr. Limbaugh to an eight-year, $400-million contract extension this week, the company now has some hefty bills to pay.