It would be extremely nice if Confluence offered the ability to respond to specific comments on a page, instead of just the ability to comment directly to a page.

Also, if comments could then be threaded, expanded, and shrunk baased upon their subject matter it would be amazingly helpful.

Ex:

• Comment
  Re: Comment
• Re: Comment
  Re: Re: Comment
  + Comment

Basically, this would add nicer discussion abilities to Confluence, similar to that of a forum.