What are Google Wave's most powerful features?

Open-source API and extension tools

Google Wave is open-source, so developers can make variants of it.
Wavescan be embedded into a web page, potentially allowing blog articles,and the associated conversations, to exist simultaneously on the weband in your wave client.
Google facilitates Wave "robots"which are automated participants in waves, with the ability toautomatically perform actions in response to certain events. Forexample, they might publish a wave to a blog, and then publish the blogversion's comments to the wave.
"Gadgets" can be placed inside waves; for example games and mini-tools.

Real-time updating of collaborative documents and discussions, tothe extent of see what other people are typing, effectively mergingemail with instant messaging.
Emails are transformed into collaborative documents

E.g. moving events between wave and calendar. I think I remember that. Maybe wishful-thinking induced hallucination.