The premiere of Conan on TBS last night earned a 2.8 household rating (i.e. 2.8% of US TV households on average watched the show) in Nielsen’s metered market overnight data. These are not the adults 18-49 ratings we typically report on the site. We'll have viewership and adults 18-49 (and perhaps other) demo group ratings later today.
Update (3): TBS press release is out:
Conan O’Brien’s new TBS talk show was a hit with young viewers Monday night, delivering an audience with a projected median age of just 30. Conan – which featured guests Seth Rogen, Lea Michele and Jack White – was watched by 2,451,000 adults 18-34; 3,285,000 adults 18-49; and 4,155,000 viewers.
That 18-49 viewership is about a 2.5 adults 18-49 rating.
Update (2) from Broadcasting & Cable:
Conan’s 2.8 beat its late night competition. In metered markets, The Tonight Show with Jay Leno drew a 2.7 household rating, CBS’ Late Show with David Letterman had a 2.5, ABC’s Jimmy Kimmel Live scored a 1.7, Late Late Show with Craig Ferguson on CBS had a 1.4 and Late Night with Jimmy Fallon on NBC earned a 1.4.
Update: I will make a guess that the adults 18-49 rating lands in the neighborhood of a 1.5 rating. Show's how much my guesses are worth! You can see what our readers guessed his first week's adults 18-49 average rating would be here.