From Yahoo News:
Fourth-ranked broadcaster NBC has quietly begun reimbursing advertisers an average of $500,000 each for failing to reach guaranteed ratings levels, the first time a network has taken such a step in years, media buyers said.
This paragraph is interesting:
Magna Global audience analysis exec vp Steve Sternberg said he saw no problem with NBC airing a reality block on a low-rated night like Saturday or even during the week if the production values were high or if it replaced other reality programming. However, “if it replaces midweek scripted hours, it could have a negative impact” on ratings and audience quality, he said.
(The Office will be replaced by Celebrity Apprentice starting January 3rd.)