Google Wave has been described by its creators as a reinvention of e-mail, but that's the least of it.

Wave has also been described as a product, platform and protocol. And it's these later two aspects of the technology that will ultimately decide Wave's success or failure.

The protocol is just emerging. On Monday, Google announced the availability of a developer instance for Wave for interoperability testing with third-party services built using the Wave Federation Protocol.

But the platform is already a hotbed of activity. On Wednesday, at the Enterprise 2.0 Conference in San Francisco, Google Wave product manager Gregory D'Alesandre discussed how the Wave platform has been developing. He provided examples in the form of brief presentations from Novell, SAP, and ThoughtWorks, companies that are building on the platform.

D'Alesandre emphasized that Wave is "a real-time collaborative platform" and "an authenticated real-time communications infrastructure for the Web." In other words, if Wave threatens anything, it's SharePoint rather than Exchange.

But Wave aims to co-exist rather than kill. Google's focus is on delivering an open collaboration architecture that anyone can build upon, one that's hopefully more appealing than proprietary collaboration and communication systems.

Novell VP of engineering Andy Fox, who participated in D'Alesandre's presentation, made that point succinctly: "The real-time web doesn't need to be controlled by one company," he said. "It's not a walled garden."

It is early still in Wave's life-cycle so many questions remain unanswerable. Wave hasn't even been publicly released after all. But a Wave ecosystem is beginning to take shape and Google is willing to draw a sketchy road map.

There will, for example, be a way for Wave gadget developers to sell their creations, to consumers, as has been previously reported, and to businesses.