"Breaking The Late-Night Sitcom Rule"

: Commentator Andrew Wallenstein explains why.

ANDREW WALLENSTEIN: Watching comedy at 10 p.m. might seem a lot like eating pizza for breakfast. There's no reason you can't, but I just don't. But it's a show that relentlessly mocks the TV industry that's about to break the sacred barrier, NBC's "30 Rock."

(SOUNDBITE OF TELEVISION PROGRAM, "30 ROCK")

M: (As Liz Lemon) Where are Tracy and Jenna? We're supposed to be rehearsing.

M: (As Tracy Jordan) Sorry we haven't had time to get into our costumes yet.

WALLENSTEIN: "30 Rock" and "Outsourced" are moving in at 10:00 because the show NBC wanted to put there had production delays, and NBC had more comedies than they knew what to do with.

: 00. Think back to ancient television history, and you'll recall some of the great successes NBC has enjoyed in that hour, like "LA Law" and "Law & Order."

(SOUNDBITE OF MUSIC)

WALLENSTEIN: The hit medical drama "ER" stayed in that slot for 15 years.

(SOUNDBITE OF TELEVISION PROGRAM, "ER")

U: (As character) Surgery - on its way.

U: (As character) Pulse is weak!

WALLENSTEIN: But now, 10:00 is on life support and not just at NBC. Ratings have cratered, and there's no one reason why. But here's two to consider. Ten is often when people with digital video recorders watch programs they've been saving, and cable channels often put their strongest programs on at 10:00, like MTV's "Jersey Shore."

: 30 just by stopping one show and starting another. Keeping the 10:00 audience around at 11 makes the affiliates happy because more viewers could stick around for the local news.

WALLENSTEIN: There's no reason NBC can't make comedy work after 10. At the end of the day, good TV is good TV, even when it's quite literally at the end of the day.

: Andrew Wallenstein is senior editor for the website Paid Content.