This is very likely derived from Google Docs, not Wave. The spreadsheet app has been based on this approach (immediate synchronization via operation transforms)

This is very likely derived from Google Docs, not Wave. The spreadsheet app has been based on this approach (immediate synchronization via operation transforms) since way back, and the document and presentation apps were rewritten to the same approach a few years ago. It sounds like they're now simply opening up that backend for third parties... which is pretty cool, actually. (Background: I worked on Writely, the original Docs word processor. I wasn't involved in the work described here, but saw some of it happening. It's nice stuff.)