One aspect that I've always been unsure about, with Stack Overflow, and even more with sibling sites like Physics Stack Exchange or Cross Validated (stats and probability), is the voting system. In the physics and stats sites, for example, not rarely I saw answers that were accepted and upvoted but actually wrong. The point is that users can end up voting for something that looks right or useful, even if it isn't (probably less the case when it comes to programming?).

Now an obvious reply to this comment is "And how do you know they were wrong, and non-accepted ones right?". That's an excellent question – and that's exactly the point.

In the end the judge about what's correct is only you and your own logical reasoning. In my opinion this kind of sites should get rid of the voting or acceptance system, and simply list the answers, with useful comments and counter-comments under each. When it comes to questions about science and maths, truth is not determined by majority votes or by authorities, but by sound logic and experiment. That's the very basis from which science started. As Galileo put it:

But in the natural sciences, whose conclusions are true and necessary and have nothing to do with human will, one must take care not to place oneself in the defense of error; for here a thousand Demostheneses and a thousand Aristotles would be left in the lurch by every mediocre wit who happened to hit upon the truth for himself.

For example, at some point in history there was probably only one human being on earth who thought "the notion of simultaneity is circular". And at that time point that human being was right, while the majority who thought otherwise were wrong. Our current education system and sites like those reinforce the anti-scientific view that students should study and memorize what "experts" says, and that majorities dictate what's logically correct or not. As Gibson said (1964): "Do we, in our schools and colleges, foster the spirit of inquiry, of skepticism, of adventurous thinking, of acquiring experience and reflecting on it? Or do we place a premium on docility, giving major recognition to the ability of the student to return verbatim in examinations that which he has been fed?"

Alright sorry for the rant and tangent! I feel strongly about this situation.