zlacker

>>pg+(OP)
The problem lies within the deeply nested threads that continuously go back and forth between a few select people. Most of the mean/dumb comments on the first level thread are downvoted or flagged and moved to the bottom. This makes it easy to read the high quality comments - just look at the top.

The problem occurs when you start reading into a nested thread of comments. Users will sometimes argue 4 or 5 times back and forth, often becoming mean and uncivil. What results is a somewhat personal discussion among a few people that doesn't fit in with the rest of the thread. While the quality may actually increase the deeper you go into a thread, the relevancy to the original thread decreases (which matters most).

I think that this behavior is what is hurting HN's overall quality. Uncivil and deeply nested threads like these are hard to keep track of and deeply get out of control.

The solution:

  - hide deeply nested threads (greater than 3 or 4 comments deep) and
    let the users choose to show them

  - promote commenting in higher threads (this will come as a result 
    of hiding deeply nested threads) 

  - hide or lessen the visibility of threads consisting of comments
    from only 2 or 3 people

>>solips+P8
Occasionally intelligent discourse only begins several comments in. We wouldn't want to exclude that.

If "karma whores" drive the system, then the incentives created by this change would drive them away from commenting on sub-threads. I guess "kw" probably already post something snarky right under the top comment (and probably time it).

The third of your points is your best idea (imho). Comments among just a few people are less likely to be generally interesting.