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Late-night television ratings fell during the first four days of a Hollywood writers' strike as viewers switched away from repeats of The Tonight Show With Jay Leno and Late Night With David Letterman.
NBC's Leno had the steepest drop, losing more than 750,000 homes, according to Nielsen Media Research figures supplied by the network. CBS's Letterman lost around 330,000 homes, NBC said.
"It doesn't bode well, and this is just the start," said Brad Adgate, head of research at the New York ad agency Horizon Media.
"It could be more catastrophic, but there's still a concern of where did these viewers go and will they come back."
Networks began airing reruns when the Writers Guild of America called a strike over payments for the use of TV shows and movies on the internet and mobile phones. Late-night shows were among the first that went to repeats as the walkout halted production on some programmes.
Leno fell to a 3.3 rating from 4 the previous week, and CBS's Letterman fell to 3.3 from 3.6, according to General Electric's NBC. Each point equals more than 1 million homes.
Putting the talk shows into reruns does more than hurt ratings.
Michael Winship, president of the guild's eastern unit, said it also prevented studios from promoting holiday movies by scheduling the actors to appear on the shows.
"That would apply to their advertising, too. They're reluctant to do an ad buy on a talk show that's in repeats."
Winship, the writers' guild's eastern president, criticised comedian Ellen DeGeneres, a guild member, for resuming production of her talk show Ellen after shutting down for only one day.
DeGeneres resumed taping because the production company, Telepictures Productions, risked legal action from the 220 stations that buy the syndicated show, the company said.
A spokeswoman said DeGeneres was not in violation of union rules.
"She is performing, improvising, not writing.
" Bloomberg