I'm still amazed that almost everyone just laughed at Wave. We're still trying to break the hold of a proprietary document format (.doc), and now platforms like Google Docs have a proprietary protocol for real-time changes. Google offered us an open, federated version of that protocol - I think we should have seized it with both hands.

Like most Google open source projects, the open-sourcedness of Wave was open-washing, nothing more. To my knowledge there aren't a lot of Wave services floating around out there, and Wave's codebase was highly coupled, making it difficult for anyone to create a server.