Ask PG: What's the deal with search on HN?
The explanation is a lot less involved than your question: what makes users happy is not features, but the quality of the submissions and comments.  So I focus on the latter instead of the former.  The result is a spartan site with good content.There's a YC funded startup that may solve the problem.  If they do I'll use them.  But frankly the issue is not at the top of my list.  This is a classic example of how one should give users what they want, not what they say they want.  Lots of people say they want search, but I would be suprised if there was a single user who'd left HN because it lacked search.  Whereas if I let the frontpage get filled up with crap, or the comment threads filled up with mean or stupid comments, people would start leaving pretty quickly.  So almost all the time I spend thinking about HN is spent thinking about how to avoid that.