I made it up. But for exponentially growing ID, log(ID most recent / ID first post) is proportional to age of account & that's boring -- the nonlinearity is wh

I made it up. But for exponentially growing ID, log(ID most recent / ID first post) is proportional to age of account & that's boring -- the nonlinearity is what makes the measure 'fun' (I use the term loosely). It agrees with some notion of the 'good old days' when Startup News was a fishbowl we could all look in on, and early HN participants were Founders not only of startups but also an online community. I agree though, there are probably more interesting measures one could come up with.