Sure enough, that was the message O'Brien gave his TV audience: go watch Dave. As in David Letterman.
O'Brien's monologue was a touching tribute to Letterman, whose late-night NBC show O'Brien inherited and, as O'Brien candidly admitted, nearly lost. O'Brien credited an unsolicited appearance by Letterman as a guest with restoring O'Brien's own morale as well as his staff's.
O'Brien and last night's first guest, Patton Oswalt, spent much of their time struggling to explain what Letterman meant to them and to other comedians of their generation.
Even if I hadn't already planned to do so, it would have felt wrong to ignore O'Brien when, at the stroke of 11:35, he frantically urged us to change the channel. It genuinely seemed to mean that much to him.
As far as I know, every one of Letterman's direct time-slot competitors implicitly or explicitly steered his audience to Dave last night. That's a gesture of respect unimaginable for anyone else. It certainly wasn't one extended to Leno. It has to hurt the insecure Leno that for the current denizens of late night, Letterman, not Leno, is their touchstone. Letterman is their Carson.
My entirely unscientific assessment of the coverage of Letterman's retirement is that it has been more extensive and a lot more admiring than the coverage of Leno's was. I don't think it has anything to do with Letterman being better-liked (I don't think he is). More entertainers and critics just seem moved to express how much Letterman meant to them.
About Letterman, I have to admit that, as with O'Brien, I've never been a fan. But I have to give him credit for having inspired so many others. To get the kind of praise he has gotten over the last couple of months, he had to have been doing something right.