I dont know if I'm a 100% correct but this is rendering static parts that are serializable in the server. But instead of as HTML its in a custom format (I'm guessing something very similar to virtual dom representation of a component). But they are better than static HTML rendering because the components can maintain state even though parts of it are rendered on the server. I'm very excited for this and I'm just beginning to build a POC for Next.js from tomorrow. May be when this becomes stable we'll be able to use it via Next.js.