CNN isn't entirely wrong in promoting that the network attracts a bigger audience, overall, than Fox News Channel or MSNBC. But those claims also amount to a double-edged sword assuming that the Turner-owned channel actually wants to cash in on the data.
Understanding what CNN is talking about (there's another full-page ad in today's New York Times) is pretty arcane stuff, but the bottom line is that CNN attracts more unduplicated viewers than its competitors. The channel is using the same kind of measure known as "cume" (as in "cumulative audience") in radio.
In radio, news stations tend to have a larger cume than talk stations, because more people tune in to find out how traffic's moving or get news updates. By contrast, fewer people listen to talk, but if they like a host, they'll stay tuned for a considerably longer period of time.
The exact same dynamic is happening in TV. Viewers of Fox News and MSNBC -- many drawn to the channels' perceived ideology and opinionated, foaming-at-the-mouth hosts -- plant themselves in front of the set for hours. So while fewer people watch, the number watching at any given moment -- which is what the rating reflects -- is higher than CNN (especially in FNC's case).
So what's the problem? Only that CNN's boast about reaching more people also exposes that people drop in and out of CNN -- and thus are less like to sit through a commercial pod. At Fox, a smaller number of people watch over the course of a day, but they watch for longer stretches -- indeed, one can picture many leaving the channel on almost as background noise -- and are less likely to flip away during the ads.
If CNN wanted to really be aggressive about it, the ads could say as follows: "CNN is the only true news channel. Fox and MSNBC give you more talk, less news." But the "So what?" and "Duh" factors for anybody paying attention are pretty high there, too.
As is, MSNBC and Fox have dismissed CNN for grasping at straws -- for attempting to change the rules, essentially, because it's losing on the scoreboard.
But the network isn't lying when it says that it's "#1 in total TV and web consumers vs. Fox News and MSNBC." Beyond feeling good about being able to say that it's winning at something, however, it's a milestone without any real payoff -- other than the fact that when viewers want to briefly check to make sure the world isn't falling apart, more of them tune to CNN ... and then just as quickly, leave.
If you can fit that on a billboard somehow, more power to you.