I dont know whether this is a good thing or not.... The best nuggets of information on HN are at the mercy of a good soul digging up the link and dropping it on a new thread.
You'd think that this knowledge retrieval/storage problem could have a more elegant solution built by the HN folks. Example solution: Topic X stored in category, ranked to the top, its next 'commit' or successor is chained on kind of like how unroll works with twitter.. but with long HN threads instead.
Think a 'git tree' of knowledge descending down, with merges too maybe...
Engh.. maybe thats part of the charm of HN... the old school style message board.