I'd argue that the discussion board, like the social environment of today, has grown more accepting of those who don't really have anything to add to conversation. I think that the discussion board has just adapted to fit the needs of everyone who posts inside of it, for better or for worse.
Severly off-topic replies are punished, I'm sure... But for the most part, I don't think anyone gets too off topic. I happen to think that there's an abundance of sarcasm, that doesn't quite add food for thought in an orthodox way, but that doesn't make it discredable.
I personally feel, though, that the comment before "You mean delaying women becoming terrifyingly ugly when they age past 30?" was more off topic. I think it went something along the lines of "Let's make a pill that stops menopause."--but with very poor use of punctuation.