[snarkyturtle]

React in particular, however, was specifically made to handle the state of just parts of the UI on Facebook (like notifications). You could build out a static site but let React handle something more complicated and it'll work just as fine, if not better.

It just so happens that the extensibility around React led to stuff like redux and react-router that's perfect for SPA's, but at its core it's just a View layer that could live alongside a traditional site.