Windows Phone 8 Live Apps
Back with the launch of Phone 7, Microsoft had shown Live Tiles and it became the most talked about feature for Phone 7. Unfortunately, it remained as the most talked about feature and didn't influence the sales much. Later we saw that the reimagined Windows 8 also heavily used the same live tiles and look and feel and we start to use "Metro" as the new user experience paradigm. However the term metro landed in some trouble and since then we have been exposed to multiple new ways of addressing this new user experience - modern UI, windows 8 UI, Windows 8 Store Apps and now the Microsoft Design language.
Anyway, back to live apps. The concept is really simple, as also explained here. Any application that has a live tile, i.e. a tile that updates its content dynamically is called a live app. Given this explanation, it is hence obvious that Windows 8 also has live apps. Personally I don't see any significant benefit of this. I was happy knowing that I could build an application conforming to the new design language and it would either have a static tile or a live tile (based on needs). Now i have a live app that has a live tile.
So the alternative for static tile is a static app? But an app will not be static as it will have data that is updating. A static app is like HTML pages which are written and published once, but who works with static HTML pages these days? So finally we have a live app with live tile and just "an app" with static tile... phew! so much for the jargon.