It's quite clear from his context that he meant "decay" as in "become mean and nasty", not "become unpopular."
In that sense, yes, 4chan is absolutely a perfect example.
In that sense, yes, 4chan is absolutely a perfect example.
I know you're the creator of 4chan, and are necessarily going to see it "at its best", but surely even you must agree that many parts of it (especially /b/) behave badly?
More anonymity = discussion tends towards thought provoking, creative, honest, offensive