|Most blog forums contain debates not discussions. People tend to only respond to thoughts with which they either totally agree, or totally disagree. People who sort of agree or sort of disagree just read on. This concept gone nuclear (reddit) makes comment sections arenas for extremes even when most readers are not necessarily extreme.|
Threaded discussion forums are more fit for pleasant campfire conversations than debate. Debates need an arena more like a game show with two or more teams taking turns against e/o.
You can classify comments in three ways:
+ Agrees with point, goes further in depth.
- Disagrees with point, explains why.
0 Neutral. Kind of a wildcard. Could be used to clarify something unknown to both sides or to say something really funny.
Anyone can jump in on any side. Comments can be modded on PG's "How to Disagree" scale, DH1-DH6.
Lots of debates come down to personal preference but at least you'd be able to easily break down the supporting arguments for "foo" being better than "bar" if you're looking to buy one or the other.
News.yc is a bit different. There is a fair amount of, "Ask YC" and other posts that fit the campfire model better than the debate model. Perhaps only deeply nested comment trees, usually signifying tit-tat style discussions, should fall into the debate model.