In my scenario, I have a requirement that only one reply can be posted per forum post.

Question
How can this requirement be implemented? I am not asking for code but just a high level idea of the changes that I will need to make in code/user control. Names of code files and usercontrols would be very helpful.

I think I will have to make all the Reply buttons/links invisible if a reply already exists. Also, I will need to make the quick reply section invisible if a reply is already there.

May be a feature where max number of replies to a forum post can be set using some configuration setting at a forum level. This would be very useful.