This isn't another story about that dress, or at least, not really.
It's about the way that humans see the world and how until we have a way to describe something, even something so fundamental as a color, we may not even notice that it's there.
Until relatively recently in human history, "blue" didn't exist, not in the way we think of it.
As the delightful Radiolab episode "Colors" describes, ancient languages didn't have a word for blue — not Greek, not Chinese, not Japanese, not Hebrew. And without a word for the color, there is evidence that they may not have seen it at all.