Miguel de Icaza: I envision a system in which we can remotely manipulate desktop applications through HTTP. The same idea that I pitched a few years ago on top of CORBA. The difference this time is that writing the client code is trivial, unlike the previous attempt where writing the client code to talk to a CORBA server was very difficult.
Update: Matthew Barger wrote to point out a presentation he gave at an O'Reilly Mac OS X Conference back in 2003: "Give Your iBook a REST".