When you have the expertise to judge the post you don't need to read it - because you allready know everything in it. Ok that was a bit too strong, there are problems that knowing the answer you can easilly judge that it is right, but to come at the anser is quite difficult (although there is an algorithm to do that just look at all possible answers - and if one is right then take it). But I would argue this is the minority of problems we encounter in our life. Perhaps on a forum for programists this is a bit biased - quite often the answer can be directly translated to code and by running the code you verify if it was right, but still it does cover only a fraction of all discussions.