The format of the post is also quite nice; a few short points with illustrations and a clear takeaway.
For larger ones, we provide lifecycle hooks so you can set up these subscriptions manually. In componentDidMount() and componentWillUnmount() you can subscribe/unsubscribe to some sort of messaging system, and when you receive the message call setState(). Usually you only need to do this in a few places and the regular React dataflow will carry you the rest of the way.
Does that make sense? We should probably write up this technique.
Or, instead of an event-based approach, you could could pass in an object and use Object.observe() to observe state changes.
It looks like React just implements the view in MVC, so you still need a separate way to observe the model.
The part of the architecture which has had the biggest impact on my code: the relationship between a component and it's subcomponents. A parent component can only pass "props" to it's subcomponents (ie it can't pass state, which is easily mutable). And a child component can only call a function on it's parent if that function is provided to it via props (ie a callback).
This design has forced me to reason about the interface between components (open/closed principle, law of demeter, etc) and has really improved my code.
Also, the team is very active/helpful in their irc room.