Just to add to the previous poster's comments, Alan Kay seems to also consider the internal state of a "cell" (or object) to be private and responsive only to external messaging. If you extrapolate this to a network I personally see a "colony" of objects that are not "aware" of each other aside from their neighbours' messages, and the whole thing starts to seem like it has a lot of the features we see in modern functional programming today. I don't think this is particularly coincidental, since functional approaches are born from lambda calculus and Kay mentions in these emails a desire to incorporate algebras into his objects (aside from the biological nature of this type of cell communication).

Alan, if you're in the comments section I'd love to hear your thoughts on what you think of the resurgence of functional programming in the modern day and whether anything, other than perhaps languages like Erlang, has approached your original ideal.