From here:

Sens. John McCain and Barack Obama aren't the only ones courting swing voters as the 2008 campaign shifts into its next phase. The ferocious battle for cable news viewers is moving into its own general election mode -- and CNN is striving mightily to keep its primary winning streak going.

The cable news network was the biggest beneficiary of the drawn-out Democratic primary, averaging 1.11 million prime-time viewers this year, a 50% boost over the same period last year. It's the best performance by the channel since the invasion of Iraq in early 2003.

In all, CNN gained an average of 368,000 prime-time viewers through June 1, compared with Fox News' 190,000 and MSNBC's 224,000, according to Nielsen Media Research.

But even as its ratings swell, the network faces a rising challenge from MSNBC, which is riding high on the sharp-edged opinions of hosts such as Keith Olbermann, an outspoken Bush critic. And it still has not caught up with dominant Fox News and its popular right-leaning commentators.