The question is what does it mean for application to be "running". In the past I remember closing applications down when I wasn't using them to save memory, now

The question is what does it mean for application to be "running". In the past I remember closing applications down when I wasn't using them to save memory, now if I run an application I generally won't close it until I shutdown the computer. Also many applications will make some attempt to start you again from where you left off last time when they are reloaded and modern OSs will try and preload common applications into memory at boot.