What counts as Screen Time?

We have all heard about "screen time" and how we're supposed to be limiting it with our kids.  So, my question is, what exactly is screen time?  Officially, it's anytime you are looking at a screen whether it be a computer, TV, iPad or phone screen.  But, what do you count as screen time for your kids?

For instance...
      Does Skype Count as "screen time"?

      Does Reading on your Kindle count as "screen time"?

     Does doing homework or educational games on a computer count as screen time?
 
     Does watching Praise and Worship DVD's count as Screen time?
      
     Does doing a Wii Fit work out count as Screen time?

To be honest, I DO NOT count these things against my children's screen time, but they are only allowed 30 minutes of "free" screen time each day where they can watch a TV show or play a video game.
      It's difficult to balance screens and imaginative play/getting exercise.   So, what do you count/not count as screen time?