I think it's more that the discussion here is of a rather different nature. Sometimes it's fine for it to be the rambling, chatty stuff that happens on other fora, but sometimes you almost feel like the conversation is so serious you should direct all remarks through the chair. Threaded view if a 'formal' way of conducting discussion.

Personally, I find it a perishing nuisance. I'd rather people used the quote function properly, and addressed specific items to people using the '@' tag (@texrat!). But then, I've done more than my fair share of chairing meetings - more than enough to prefer the informality. I also prefer a more 'female', networking-forcused way of communicating.