There's inflation at work here so today's $NORM has little relevance for older nodes.

Actually, no. As far as I can recall (at least as far as 2001 or so), the value of $NORM has always been very close to 10±0.5 (that's +/i for the Unicode-challenged browsers out there).

Sometimes it has stayed above or below this band for a short while, but it's remarkable how stable the value is as a rule.

Commenting on the OP: I think the idea sucks, :) A vanishingly small number of nodes added after 24 hours or so to a thread manage to acquire a reputation of $NORM. Many of those nodes are well thought out and well written. It would be a pity to miss them.

This site is not like Slashdot. There aren't an impossible number of replies in a thread to wade through. The greatest single improvement that could be made to Super search would be to thread the resulting hits. That would improve its useability much more than some arbitrary line drawn in the sand.