I'm leaving a lot of things out of this section -- because I want to get this thing on the street rather than spending the rest of my life expanding this appendix.
On the near side, there will be extensions to the operation of the BBS, refinements, and new features.
On the far side, I haven't mentioned transportable objects (like a Hyper-Card stack that gets sent to a remote machine and then executed there), or agents that figure out where the right information for you can be found and go get it, or using the thousands of HyperBBS's idle times to compute...