I did a marathon catch-up last night. I don't have firm opinions on a lot of this stuff (I see multiple sides, and am not sure which trumps for me). However, there are a couple points I didn't feel were made.
First, on the statistics that Nilly just cited (not picking on you, Nilly. I was going to say this anyway), and about looking at Natter/Bitches during the Experimental Threads, I worry about us seeing causation where there's actually correlation. People have often commented (albeit jokingly) about changes in the lives of "us". We do have more people with small children, for example, and that's got to have an impact on how those people post. It may not be the same for every parent, or even for the same parent at different times. There is a group of Buffistas who have been here for many years (I've been here for about 4, and I know I'm a relative newcomer, although I absolutely consider myself part of the community, and people who are far newer than me), and their lives are different, and our conversations are different, in part, because of that. The needs of the community may also be different than they were 5 years ago.
Second, television discussion is different from knitting, or cats, or even books or movies. Really, the thing it's closest to, IMO, is comics. You've got stories for which one can be spoiled, but those stories are also on-going, with installments coming in regularly. I can be spoiled for a sporting event, but once it's over, it's over. In my own experience, I haven't seen last week's Eureka yet, but then, neither have I seen PotC:AWE. The first means that I don't want to see this week's till I've seen last weeks, and, therefore, have to stay out of Boxed Set, skim, and/or be spoiled. The second means that I skip over some (in this case whitefonted) conversation in movies, and then continue to participate, since my thoughts on Order of the Phoenix don't really have anything to do with not having seen Pirates. So, I guess what I'm saying is comparing making threads for tv to making threads for lunch or baseball is, to me, a very false analogy in some important ways.