When I encounter an unformatted or badly formatted post, I usually leave a comment such as this one explaining how to fix the problems rather than fixing them myself. This is not just because I don't want to spend my time fixing other people's formatting, but also because I think that it's better that they learn to do it themselves rather than having it done for them, which often seems to result in their next post being just as badly formatted and having to be fixed by someone else again.
Recently two recipients of such comments thanked me for the information (here and here). However, it seems that most people are taking a different approach and just editing posts to fix the formatting without leaving a comment. That made me wonder, on the one hand, whether my approach might be seen as annoying by some, as it results in lengthy extra-mathematical comments that distract from the math, and, on the other hand, whether we might get fewer badly formatted posts if more people took my approach.
What do you think?