• by David Goetzl  @dgoetzl, August 12, 2008

Discovery offered some insight into why it recently replaced the head of its TLC network. And it's all about the money.

As the company reported, ad revenue at its U.S. networks increased 9% in the second quarter. It cited the lower ratings at TLC as a drag. Higher sellouts and pricing led to the increase, the company said Monday, but the lackluster performance at TLC appears to have compressed the amount of salable inventory at the channel.

In late July, Discovery let network president Angela Shapiro-Mathes go; she had been in the position for a little over a year.

Discovery said that overall revenue at its domestic networks jumped 11% to $549 million in the second quarter, and distribution dollars grew at a faster 14% pace than ad revenues. The figures do not include the $22 million in revenues from the Travel Channel last year; the network is now owned by Cox.

However, Discovery continues to use its sales force to represent the network, and indicated that the arrangement helped with its improved U.S. performance.

The company does not break out how much it takes in from ad revenues, only providing the year-over-year rate of growth.

Including global operations (excluding Travel Channel), total company revenues were up 13% to $863 million in the second quarter. Discovery derived a significant 36% of that revenue from its international operations.