Except without nested/threaded discussions. I don't know why the social web loves flat comments so much.
while(true) {
Start simple
Add features
Declare it too complex
Abandon it and start again
}YouTube is a pack of raving howler monkeys with the occasional howler monkey researcher at the periphery. And, in fact, YouTube used to have threads, but they were still threads full of howler monkeys.
I'm talking more like your classic bulletin boards producing high quality content, like MetaFilter, Something Awful, and the like.
I'm not intrinsically opposed to threads, but I'm not sure they're super beneficial outside of technical contexts or in an environment where people are expected to break a larger conversation off into it's own little set of discussions to keep the high level conversation easy to understand.