On 4chan, it's ignorantly used as a sign of disapproval and the oft-used "SAGE THIS SHIT!" is posted. Sometimes "sage-bombing" comes along with the territory. Quite sad, 4chan, quite sad indeed.
that's only on the parts of 4chan that aren't /prog/.
people misusing sage on /prog/ are just ignorant faggots who can't tell the difference between /prog/ and /b/.