From the article they published in Advanced Materials, it seems the ink actually contains silver (the element) nanoparticles in a colloid. I'm surprised that the resistance is still that high.
I can see this as part of one of those electronic kits (http://www.kosmos-shop.de/Elektronik/easy-elektro-start/kosm...) that I got as a kid. Instead of having physical metal rods to connect all the circuit elements, they would supply a couple of these pens and a stack of papers.
It might reduce the obstacles for getting more kids into science and engineering.
For the real stuff, I am not so sure...
Neat, but seems like a novelty.
As far as usage in teaching circuits, it wouldn't be very useful after the first class. The bulk of learning about circuits is math.
what happens when you put too much current through? Does the notebook go up in flames? Having seen many fellow classmates flip polarities to watch caps explode, i can see them lighting up their notebooks with this..
How is this different from a Circuit Trace Pen [0]?
... a conductivity of 50-100 milliohms per square per mil ...
That's pretty bad. Cue the video of him measuring 50 Ohms for that small scribbled line...