[chris_wot]

Have we also talked about first topic reply advantage? How many people will bother to read past that first massive 50 reply tirade about politics to get to anything else?

How do you handle that anyway? If you make it a flat discussion, if someone brings up a new topic (in other words, a branch) then how do you respond to it if there were lots of responses between the time you wanted to reply and the time the original post was made?

If you have a long distance between the original post and the post you are responding to, then that means that the audience loses context and don't know what you are talking about - thus instead of asking "how many people will bother to read past that first massive 50 reply tirade?" you now have to ask "how many people will bother to read past the first insightful comment?"

Basically, how do you keep the thread of discussion without using indenting, or expanding/contracting the discussions? I can well understand that StackExchange needs to keep discussions punchy by design, because it's about keeping information succinct in order to properly answer questions, but on a site like HN that is designed for discussion I think that flat discussions would be an absolute disaster!

Slashdot actually allows for flat discussions, try using it sometime and I think you'll see that it's a nightmare.

[kijin]

> the audience loses context and don't know what you are talking about

In most forums, you just jump quote the post you want to talk about. Doesn't matter if you're on page 144 and the original post was on page 36. Click "Quote" and phpBB/vBulletin automatically adds a link to the other post.

And it's an unholy mess to wade through a 144-page forum topic. A lot of people just quote the whole post to add a one-liner. It's a nightmare. Any long thread is probably 90% quotes and 10% new content. Just the other day I was trying to find some information in an XDA Developers forum. I gave up after a dozen pages or so. Too much garbage thrown in between useful content.

On HN and Reddit, on the other hand, people quote one another much less frequently. For example, I only quote other comments if I want to say something specific about a particular passage. Here, we get along just fine without excessive quoting, because the context is already there. HNers understand the cost of context switching.

I wouldn't want to read a HN thread where 90% of the content was made up of quotes a.k.a. context-switching crutches.

[tripzilch]

> How do you handle that anyway?

Reddit does it by limiting both the tree depth with a "continue this discussion" link (often seen in pun-offs) and the vertical tree length / number of replies with a "load more comments" link.

This ensures that the top thread is never really more than 1.5 screenlengths. Works very well IMO.

(For completeness sake, there's one other comment hiding feature, "Comment score below threshold", but that serves a different purpose--a bit like HN's [dead] comments except you can collapse/expand them and reply to them).