[dragontamer]

There's no way to automatically know if an answer from 4 years ago is still relevant today.

Maybe it is, maybe it isn't. Trying to tie an algorithm to "age decay" is the wrong solution, because it will decay too quickly for some questions, but not quickly enough for other questions.

[stevenwliao]

It's softer than the original proposal: instead of archiving an answer (reducing vote weight to 0) at an arbitrary time, we do it gradually at an arbitrary rate.