Just something that I saw on another forum and I think this one can use it as well. Just a simple icon next to the thread starer's name or post when they make additional comments for a thread they have already started. I find myself confused when subsequent posts in a thread refer back to the original post and I cannot understand who they are trying to direct the comment to, or there such cases.
The explanation might be more confusing than the problem, but the solution will probably wont be.
Just a suggestion that I thought would probably work here