yeh i was wondering that too... but that's what I like about React actually. A simple skin for complex views on top of a server-side language (Java/Clojure for me).

It makes more sense to me since I don't want my entire site to be overly Ajax-y. I'd rather only feed a few initialization variables to js & have most of the site logic/navigation/variable-injection coming server-side from a nice persistence layer.