The UI from Google was little more than proof-of-concept. The ability to sync arbitrary data, not just chat text, on the fly is what will make Wave useful if it

The UI from Google was little more than proof-of-concept. The ability to sync arbitrary data, not just chat text, on the fly is what will make Wave useful if it ever sees wide adoption. That really is the core concept and not chat, as many seem to think. It's not accurate to say that there's no core concept.