[mcguire]

Note that "...how you might handle objects that don't respond to messages" refers specifically to what happens when you send a message (or call a method, in the parlance of most non-Smalltalk languages)

    thingy.spamford()

and the thingy doesn't implement a handler (or a method) for spamford. It has to do with this paragraph from the original, original post:

"Kay argues (correctly, IMHO), that the computer revolution hasn't happened yet because while our bodies are massively scalable meat computers, our silicon computers generally don't scale in the slightest. This isn't just because silicon is slow; it's because of things like print customers.fetch(customer_id).last_name not actually having a last_name method, throwing an exception (assuming it compiled in the first place) and programmers getting frantic late-night calls to bring the batch system back up. The only real upside is that it offers job security."

This has nothing to do with network protocols.