Typically when I hear "Single-page application" I think of web apps that perform a dirty trick like starting out logged in making the main content section of th

Typically when I hear "Single-page application" I think of web apps that perform a dirty trick like starting out logged in making the main content section of the page an empty <div id="content"/> and letting some javascript add the necessary dom elements as information about them comes available through some asynchronous request. Clicks on page elements that represent some user interaction with the app should usually not trigger a whole-page reload, but instead fire some On-Click action resulting in (maybe) some data being sent to the server and (maybe) some new content being added or updated on the screen without changing the URL of the loaded page. The client might long-poll or maintain a websocket so that new information from the server can be received without a user action. These are the types of patterns you don't normally see in "any other web app" that differentiate an "Web 2.0" SPA from "old-school Web 1.0" applications.