Google Wave Developer Preview at Google I/O (2009)

It's strange to think that this presentation of Google Wave was over a decade ago now. The concepts and interface still feel ambitious.

Although elements similar to Wave appear in modern messaging apps, it's hard to think of a single collaboration tool which provides all of the group threads, context, and dynamic widget support.

In terms of realtime group collaboration with support for dynamic elements, the most impressive project I've seen recently is Cattaz[1], a research project from Fujitsu Labs.

[1] - http://cattaz.io/