• by Wayne Friedman , September 3, 2009

After two months of "The Tonight Show with Conan O'Brien," the results are still a mixed bag when compared to other late-night fare. However, "Tonight" scored its biggest advantage over the "Late Show with David Letterman" -- 63%, earning a 1.2 rating/5 share among 18-49 viewers for the week ending August 28. Letterman earned a 0.7/3.

ABC's "Nightline" came in at second place for the week with a 0.9/4.

O'Brien averages 1.53 million adults 18-49 to Letterman's 935,000 viewers. Adult 18-49 viewers are of key importance to advertisers.

"Late Show," however, beat "The Tonight Show" in viewers for the eighth straight week in a row. For the week ending August 28, "Late Show" had 3.32 million total viewers versus 2.78 million for "Tonight." But it was ABC's "Nightline" that topped both late-night talkers with 3.5 million viewers.

Season-to-date numbers have CBS' "Late Show" averaging 3.7 million viewers and NBC's "Tonight Show with Conan O'Brien" taking in 3.3 million viewers. ABC's "Nightline" leads the time period among total viewers with 3.8 million.

Among 18-49 viewers, "The Tonight Show with Conan O'Brien" has a season-to-date average of 1.3 rating/6 share; with CBS' "Late Show" and ABC's "Nightline" tying for second with a 1.0/4.

While CBS touts "Letterman" in total viewers, NBC touts that O'Brien has lowered "The Tonight Show" median age dramatically -- something that is important to national advertisers. O'Brien's audience is now at 46.2 years old -- more than 10 years younger than "Nightline's" 56.5 and more than 11 years younger than Letterman's 58.0.

All has this been helped by the stronger 18-34 viewership of "Tonight," which is more than double Letterman's young audience -- 750,000 to Letterman's 307,000 for the week ending August 28.