Web developers often watch with envy how mobile platforms use push technology to send important information and messages from their backends (or from one device) to several mobile devices in real time. It's not clear how to achieve this for the web; consequently many developers settle for polling their backends — asking intermittently are there updates....
While the polling approach is simple and works for the most part, it burdens the client and server unnecessarily, leading to chatty applications, and can quickly impact memory, network, and bandwidth resources.
With push, when an event (for example, update) occurs on the server, probably triggered by a client, the server broadcasts a notification (ping) to all registered clients about the update so they can act accordingly. Therefore, as a store manager, I can change the price of an item in my products view then save the change, and have the new price immediately show up on the views of the cashiers at the POS terminals...