We ourselves have been toying with this idea for some time now. I think that it will happen eventually, but at the moment, seeing as we are so new, we want to give the forums time to grow and flesh out before dividing all of the posts. It has also been brought up that having individual chapter threads might be difficult, seeing as the discussion of one topic so very often leads to another, which may or not be within the same chapter. Thanks for the comment though! We are always happy you hear the members wants & needs!
Having been a member on various forums for awhile, I have to agree that I think it could be difficult to separate them out, and also that it could lead to restricting conversation. (I.e. someone gets inspired about something in PS chapter 1, makes a remark about something that we don't learn about until chapter 12 or something, and then everyone says, "Sorry, not here, you should discuss that in the other section").
I'd also add that if you were to make specific chapter-by-chapter sections, it would still be a good idea to keep a "General Philosopher's Stone" section as well, rather than forcing people to choose "does my comment fit better in chapter 12, or 14?" and so on.
Perhaps it could be sufficient to simply have a set of threads in each section for chapters? To be clearer...In the PS section, have a thread titled "Chapter 1" where you discuss things specifically pertaining to chapter 1" and have it specially designated by admin/mods/what have you? And then there could also be other threads of general discussion, but in my experience, if things are split up TOO much, you lose posters because of confusion on exactly where to post. Keeping things more together fosters more community, which even on a strictly academic board, is still important, I think.