It's quite common when I ask a question and people put answers, someone else comments on the answers. That's perfectly fine. However, the person that gave the answer would comment, thinking that the person commenting was the person that asked the original question.
That can cause some confusion, because the person answering will comment back and something just doesn't quite fit with the content of my question and the comment from some random third party - this confuses the answerer.
I suggest making it clear when the person commenting is the person that put the question. It could be by putting a certain background color on the name of the commenter, as you see on many blogs.
As BoltClock points out, there is already a background color for comments of the person that posted the question. Neither I nor the answerers that were confused about this noticed it. Now that I know it, I must admit it's strange I didn't notice it - but even so, it could indicate a need to highlight it in some other way. Any suggestions?