That's relative, isn't it? Below average is effectively negative for most purposes. Contrary, the Root Mean Square of a sinusoid AC supply can't go negative, for example. Economy (or socio...) is maybe not that simple, but still based on a balance between giving and receiving. What's interesting then is the average of the slope: zero for AC pretty much by definition. While stability is important, growth is too, economically speaking, so the derivative would need to be normalized under an average, so we are back to square one.

That's to say, of course people can be on the decline.

I don't know the answer but if there is a floor at 0, that would mean at this point you have nothing to loose, so that could backfire. But you probably get incarcerated before you reach some threshold level.

HN has fault habdlers in place for accounts with karma going too far below zero. It was a hellban at -13 for my old account. I did keep writing for weeks before I noticed, the exercise of which was still rewarding in a way, and I still receive few answers now. Sometimes I suspect mods to the visibillity. I reinterpretted rangeban to mean banned beyond a certain range (as opposed to how it is commonly used: the ban of a whole range of possible identities).