Who can see my comments on friend's Facebook posts?

[Jaybo]

Let's say I comment on a friend's post, and that friend had posted it with the default option of "Friends." Does that mean ALL of my other friends could see that I commented regardless of whether they know the other person? Or does it mean that ONLY those who are friends of both myself as well as the original poster can see it. How does it change if the person making the original post chose to change the audience to "Friends except acquaintences." I just do not want all of my friends seeing everything I make a comment on, especially if they do not know the person who's post I am making a comment on.

[abraXus]

all of his friends can see your comment, and all of your friends can see his original post and your comments and all of the other comments, even if they arent friends with him