The decision of making sage invisible is interesting to discuss. Like with the quote function (or greentexting), many of 4chan's basic functions have been used for more than intended function. This creates things that sometimes are not what you want to get, but should you take away the new functions from your users?
Yes, because sage isn't a new function it's one that was taken from 2chan and like the post says sage never was and never will be a downvote. It's just a way to reply without bumping the thread.
...which, based on how the boards work, is essentially a downvote.
Each thread can have x posts before new posts no longer bump it. If you sage, you are using up that thread's available space (1/x worth) without bumping. Although this doesn't "downvote" in the sense that the thread is penalized/lowered, it "downvotes" because it takes up thread space with no benefit to the thread. Not to mention, sageing is a way to express your dissatisfaction with the thread, which I think was always the point (rather than trying to actually hurt the thread).
