The "magic" functionality I think we want here is a web page that can display status info the arduino reads from the real world, as well as controlling devices. As simple as the temperature sensor we've seen, to monitoring which doors are open or closed to a web interface to control every light in the house.
Yes, exactly.
For stuff like that, it looks like the SimpleLAN might be a better choice. Its web page storage is minimal -- only 31k -- but in this thread, a user demonstrates that the SimpleLAN can interpret standard Javascript , making interactive web page construction simple and straightforward. You can do a lot with 31k of Javascript.
It has a well-defined API, too. No hocus pocus.
I believe that's the direction I'll pursue.
Many thanks, everybody.
Tom