Is the "App Cache" in HTMl-5 really a new feature
===

i am reading about HTML-5 and what are the new features it offers, and one of these features are the **App Cache** which is define in W3school website as *"Offline browsing - users can use the application when they're offline",,* but is this really a new feature?? since from long time (at least 6 years back) we have the option of browsing a web site even if we are offline since the HTML will be cached inside the browser ?? so what is this new feature means ??
BR