Sometimes I read questions on topics that are a little bit beyond my level of knowledge, and I might struggle with a point in one of the answers. I then ask the answerer in a comment to clarify, but for my own sake, not that of the original asker of the question.
I haven't really seen anyone else doing this, though, and I can see how it might be considered to be distracting from the original question. Is it okay to do this?
Note that I'm only talking about other peoples' questions.
I think asking in the comments of an answer for clarification about the answer itself is fine, and that's just what the comments are for. Answers aren't just supposed to answer the person who originally asked the question; they are supposed to remain as an archive and provide answers to future people with the same question. I think it's fair to say that you yourself are one of the first of those future people.
I do think you should try to avoid asking questions that will expand the scope of the answer significantly beyond what is needed to answer the original question. Those should be posted as fresh, separate questions. And, as the automatic message sometimes says, one should avoid long discussions in comments; they should be moved to a different channel.
