Before massive propagation of mobile device like smartphones (iPhone came in 2008) we could think of exocortex as a three level structure:
Maybe some prefer to put desktop on the first level, I do not mind.
But nowadays we have a ‘mobile first’ revolution what means that the first thing you will use to solve the problem is your mobile device – smartphone or tablet. So the structure of the exocortex still includes three levels but in different order.
But for me, sometimes it no other way for solving some problem that thinking on the paper first.