I get what's going on now.
It may have started as a demonstration of poor color encoding, white balance and perception. But it quickly morphed into a demonstration of suggestibility.
There are (at least) three dress pictures out there. Not counting the re-balanced original. The first was of a blue and black dress, probably taken with a cheap camera phone. And that started it all off. The dress, way overexposed (mis-balanced) looked white and gold (tan, yellow, etc.) But the photographer knew it was supposed to be blue and black. So they posted this and started the discussion. Finally, some professional equipment was taken out, the dress photographed and proven beyond a shadow of a doubt that it's blue and black.
But there are at lest two other photos out there. A photoshopped copy of the original (thanks, /b/tards), with the colors changed to white and yellow. And a second dress with a very similar striped pattern, white and tan. But if you look closely, its not the same one and it has been cropped so as to eliminate background cues. Now, if you show these two pictures to people, some will still say "blue and black". But its not a matter of perception anymore. Thee two photos were never blue and black. Its all about suggestion. People 'know' that its blue and black because they've been told so. So that's the correct answer.
It's sort of like the Jimmy Kimmel Man on the Street prank interviews, where someone asks a passer-by a question about something that never happened. And they formulate an answer, just to sound well informed. And they might even believe that the incident in question actually happened when they walk away.