I'd seen rumors that George Clooney would appear on tonight's episode of ER - maybe not a ton of them, but enough to make a steady stream. Even earlier today NBC would still not confirm it. It turns out Clooney (and other former cast members warning: there are spoilers in the link) did make an appearance.
NBC has been saying for a while now that it doesn't focus on the Nielsen ratings, and its performance generally seems to back it up. For what seems like weeks, NBC hasn't had any shows in the overall top 20 weekly most-watched show rankings. Despite this, I still didn't really believe NBC didn't really care.
I don't know why NBC didn't promote the appearance. My best guess is Clooney only agreed to appear if they promised not to use him for promotional purposes. That's the only reason that makes any sense that comes to mind for me. Something like, "We wanted to give a special reward to our faithful viewers, so we didn't promote it" sounds good but it seems very unlikely.
Clooney saying they couldn't and then NBC actually being behind all the rumors of the last few days makes far more sense to me. It seems far more likely than deliberately making a bold statement that NBC really doesn't focus on Nielsen ratings. Either that or I'm completely missing something, and that's certainly possible.
Though NBC programming executives may not focus on the Nielsen ratings, NBC has a whole team of PR people who do focus on the ratings. I'm sure there will be at least one press release mentioning the ratings of ER tomorrow. With or without George Clooney, the final season of ER has been one of NBC's better performers this year. It will be interesting to see what impact Clooney had even though his appearance wasn't heavily promoted.