It's an open protocol, and part of Google's stack will be released open source. So yes, eventually you'll be able to set up a private behind-the-firewall wave s

It's an open protocol, and part of Google's stack will be released open source. So yes, eventually you'll be able to set up a private behind-the-firewall wave server and federate with the private behind-the-firewall servers at other companies (presumably including a robust email-to-wave bridge).