Despite what Jay Leno may think, Americans aren't going to bed earlier, the blog TV by the Numbers reports. Nielsen ratings confirm that more people watch TV at 10pm than later on, but that's nothing new. "What the data shows is a decreasing trend of viewership between 10 and 11pm (not great news for Leno’s new time slot) and increasing viewership" at 11:30.
That indicates that people aren't going to bed earlier after all—"and if anything are staying up a little bit later now," blogger Robert Seidman writes. So why are fewer people tuning in at 10? Could be lots of things, but Seidman points to the use of DVRs.