"It glues together a lot of things that have until now been separate products," Dulaney said. "This is where users will want to be."

Even after working on the product for about two years, Rasmussen and the other members of the Wave development team still discover new uses for the tool, so he's very aware that grasping the possibilities of Wave will not be an automatic thing for end users.

That, again, is why Google decided to share Wave early with developers. "Now is a good time for developers to start picking up the APIs, building cool applications and extensions, so when we do launch later this year our users and their users can enjoy all these things together," he said.

Rasmussen and his brother Jens, the other Wave project co-founder, also learned how beneficial it can be to a Google product to have an enthusiastic community of developers around it. They arrived at Google in 2004 when Google bought their mapping startup Where 2 Tech, and went to work in creating what would become Google Maps, a service credited with igniting the mashup frenzy.

At its core, Wave lets people create a document to which multiple users can add rich text, multimedia, gadget applications and feeds, and do so concurrently in the way in which people interact on, say, instant messaging. These "waves" can be rolled back to view the evolution of the document.

It remains to be seen whether Wave will cannibalize Gmail and other popular Google products, but the culture of innovation at the company trumps those types of concerns.

"Just because we have a suite of very popular products, we shouldn't stop innovating; quite the contrary. We should always keep trying and do new, better things," Rasmussen said.

Wave is built on Google Web Toolkit using HTML 5, the latest version of the Web's markup language, and has a set of APIs designed to let developers extend its functionality and integrate it with other Web services. The protocol underneath Wave is designed for "open federation" so that the product is interoperable, and Google plans to launch the Wave code as open source.

Google expects to keep Wave as a developer preview product for at least several more months. For starters, only developers attending I/O will get access to Wave on Thursday. Google will expand access to more developers later.

Rasmussen warns that the Wave code will appear rough even to developers, so those interested should be of the adventurous type who like to be early adopters and participate in the evolution of a product.