Google took an important step on Monday in the development of Google Wave, opening its servers up to outsiders who want their own waves to communicate with the outside world.
A "wave" is a stream of messages that blends traditional e-mail, instant messaging, file sharing, and workplace collaboration tools. There have been plenty of supporters and detractors of Google Wave, Google's bid to reinvent e-mail as a combination of such services. But Google's implementation of Wave is going to be only one part of the story: outside developers will have the opportunity to build their own wavelike services using the Google Wave API set.
And those outside implementations will be able to communicate with each other using the Google Wave Federation Protocol, now that Google has opened up federation of wave servers. This means that if Company A built its own wave servers, it could interact with Company B's wave servers through a public peer-to-peer network facilitated by Google.
At the moment, this is just confined to the developer preview sandbox that was the initial proving ground for Wave. Since its launch, Google has opened up Wave to a wider audience for further testing and bug squashing, with a formal launch not scheduled until early next year.
Wave's complicated interface has not been a resounding hit with early testers, but the combination of external development and a federation service means that others could create more compelling ways to use the technology.