It's a really intriguing phenomenon that on StackOverflow, the top-most voted answer was most often the wrong answer. My initial theory was that it's staleness. That is, it might have been the best answer when the question was asked, but if you're looking at a few years later the right answer changed. But it wasn't always that.

This has very interesting implications for everything in the world, btw. Correctness does not track majority consensus.