https://www.youtube.com/watch?v=4Z4RKRLaSug
Their "World Quester 2" tutorial shines as the holy grail of consistent and ergonomic user interface and game design. The menuing system is so magnificently structured and well organized, it bring tears to my eyes. Google Wave pales in comparison.
Years later Apache moved it to read only because of low community activity.
The archived git repo on GitHub remains available to clone and revive as a fork.
wave failed for weird google organizational reasons far more than anything inherent to the product or tech