> Another new concept is the ability for either side to push data over an established connection. While the concept itself is hardly revolutionary — this is after all how TCP itself functions – bringing this capability to the widespread HTTP world will be no small improvement and may help marry the simplicity of an HTTP API with the fully-duplexed world of TCP. While this is also useful for a server-to-server internal APIs, this functionality will provide an alternative to web sockets, long polling, or simply repeated requests back to the server – the traditional three ways to emulate a server pushing live data in the web world.

As far as I know, this is not true. Server Push is only for the server and can only be done as a response to a request. It's not a WebSocket alternative.

Server Push means that when a client sends a request (GET /index.html), the server can respond with responses for multiple resources (e.g. /index.html, /style.css and /app.js can be sent). This means the client doesn't have to explicitly GET those resources which saves bandwidth and latency.