[EvanPlaice]

Isomorphic means hybrid client/server view rendering.

SPAs are (relatively) slow to load. To improve perceived performance, the view requested is prerendered on the server with the ability to capture user input. The user sees a fully functioning site while the app bootstraps in the background.

Once the app is finished bootstrapping, the user inputs are replayed on the actual app.

This fixes the problem of poor perceived initial load times that come with SPAs. Once the app is bootstrapped everything is fast/snappy as one would expect with a SPA, incl no page refreshing between URIs.

Isomorphic React is already supported. Isomorphic Angular2 (ie Angular Universal) is in the works. I don't know about Ember but I'd assume they already support it.