#3 is a good idea - Although time might be difficult to calculate reliably. Page views might be a better metric.
I sort of have this system already - I watch my karma and try and use that as a negative feedback loop (i.e. try and keep in the same general increase as other peers).
I sort of have this system already - I watch my karma and try and use that as a negative feedback loop (i.e. try and keep in the same general increase as other peers).