The "Late Show with David Letterman" is not only beating "The Tonight Show with Conan O'Brien" when Letterman is in repeats and O'Brien is running original programming, it is beating the show by a wider margin now.
Okay, it's summer; O'Brien is still new as the host; and everything needs to get settled in. The fall will tell a better story. But, still... Two weeks ago, Letterman beat O'Brien by just 7,000 viewers, but the gap last week was 280,000 viewers, with Letterman's 2.95 million viewers to 2.67 million for O'Brien.
Advertisers will tell you all this doesn't matter, that it is still all about those specific younger demographics where O'Brien still leads among 18-49 viewers, and with even better results among 18-34 viewers. For example, O'Brien had 574,000 18-34 viewers to Letterman's 315,000.
O'Brien's average viewer is also ten years younger than Letterman, and what Leno had previously as the host of "The Tonight Show." This is pretty good stuff for advertisers - for now at least.
Jay Leno said he began the same way, with an uneven start when he replaced Johnny Carson in the early 1990s. Early on Letterman was regularly on top of the heap. After a period Leno pushed to the top and remained there for his entire run.
But this isn't the early '90s. It's a different late-night environment, which also has the likes of Comedy Central's "The Daily Show with Jon Stewart" and "The Colbert Report."
The key is whether these Nielsen-derived metrics will have the same meaning, value and power to advertisers a couple of years from now, when new currencies might be produced from set-top boxes. What if data suggest that Letterman and Colbert viewers are the customers that advertisers really want, customers that will spend more money to buy their products than viewers of "The Tonight Show"?
There might even be better metrics for straight-ahead TV news viewers. Last week, in the 11:30 p.m. to midnight slot, Letterman had 3.27 million viewers to O'Brien's 3 million. But both shows were actually also-rans. The winner was "Nightline," with 3.36 million viewers.