[petercooper]

I've always found unthreaded/single threaded conversations to be better when you want the discussion to remain civil and focused. For example, on MetaFilter or Edward Tufte's board.

I wish/hope someone puts some effort into studying the difference one day though because it might just be confirmation bias on my part.

[kitsune_]

The most vile and trollish boards I know are single-threaded. It's very easy to derail a discussion.

[bunkat]

This doesn't seem to be working out too well for YouTube or any political site (HuffPost, etc) - have you read through some of those discussions lately? I don't think that single vs multi threaded conversations has any direct correlation with civility.

[HeyImAlex]

I've found that its more about scale than anything. Flat discussion can quickly devolve into... well, youtube if the number of posters completely outstrips what the moderators can feasibly moderate. Threaded and democratized discussion mitigates the moderation problem by allowing the users to kind of self regulate.

Democratized discussion has so many problems of its own though that it's a real trade off...