Google Wave wants to reinvent email, the original killer app, but it raises an old question: who actually made money from email?  Thinking back on computing history, I can think of 4 killer apps that are in a league of their own: the window-based operating system, the office suite, email, and web search.  Three of those four are industry-defining cash cows:  Windows and office for Microsoft, and web search for Google.  That makes email the odd one out; sure some people make money from the technology, e.g., spammers, but email does not fund an Microsoft or Google-esque empire.  How can something so fundamentally important to the world reap so little profits?  Well of the four killer apps, email is the only one that is federated, and couldn’t exist any other way.  Painted in that sense, email is a rather heroic transfer of economic surplus from its creators to the users.  Regardless of whether or not Google has some genius plan to make Waves into its second cash cow,  hats off to them for taking one of the boldest moves in technology in a long time.

Lots of other things have been said about Waves, so I’m not going to revisit them.  I particularly like Tim O’Reilly’s take.