Not all of these early adopters used Wave in the same way that you or I would have as end users of Google's offering. See: http://tinyurl.com/yboudhx for an example of an experimental business modelling tool built on top of Wave by SAP.

I always thought that this was the most interesting part of Wave, and the part with the most potential - at its core, it's a system for collaboratively editing documents. I hope we'll see more interesting things built on top of this core now it's open source. I always hated what Google tried to do with it, which is a shame - the tech is really cool.