The New York Times' Brian Stelter takes a look at the advertising impact after, "MSNBC cemented its identity as a channel for a liberal audience."

But Stelter found advertisers weren't looking at that angle. "So far, they say the partisanship of the programming matters less than the ratings the shows can generate," he writes.

And on that front, it is Fox News that has dominated. "In 2007, for the first time, Fox News raised more advertising revenue than the combination of CNN and the sister network Headline News, according to the research firm SNL Kagan," writes Stelter. "It estimates that Fox earned $460 million in advertising last year, while CNN and Headline News netted $434 million and MSNBC earned $137 million."

Stelter quotes CNN's COO of ad sales Greg D'Alba, who says he, "pitches the reach of CNN's platforms rather than the opinions, or lack thereof, on the programs." That, despite the Pew study out this week which shows FNC has the most balanced audience.