Alan's tastes in media have evolved to where he watches less broadcast television and more internet broadcasts. His three screens these days likely involve his laptop, iPad, and iPhone. I think for many of us, the experience is similar.
What We DoNot everybody does this. For some of us who are compulsive Internet users, we can be watching TV with a laptop, tablet, or phone handy to check up on actor profiles, obscure references in the script, or for some backstory. We may be twittering our reactions to the latest Game of Thrones episode as it's playing. We might be watching breaking news on TV and supplementing it with articles. The point is, we consume content through different media in parallel.
My 3 ScreensIn my experience, I am 100% in agreement with Alan regarding the 3 screens, although from his posts I get the impression that his screens were interchangeable, not simultaneous. I could be off on that. I'd like to add that besides 3 screens for entertainment, we have 3 screens for productivity. I propose that the computer or tablet, your phone, and an eReader, such as the Kindle can be the 3 screens of productivity.
When the iPad first came out, people kept asking me if they should get one. They imagined that they would be able to be so productive everywhere they went. Then the reality hit them that tapping out long documents on a screen is not very efficient, and that there were a lot of shortcomings to tablets, of which there was only the iPad at the time.
Since then tablets have come a long way. But, for the most part, tablets only have one screen at a time. There are some like the Samsung and Microsoft Surface that can split screen; but, I find this ridiculous because it makes for much smaller usable space.
For me, productivity typically involves reading something or watching something, then typing up my synthesis. Flipping screens back and forth on a device is cumbersome and time consuming. For this reason, hand-written and printed notes never lost their appeal. You can have media readily available for a quick read, and then the laptop or desktop to type up your synthesis. Rapid succession. No toggling.
If you substitute the Kindle or other reader for your paper notes, you have your third screen.
My work style is very visual. If it's out of sight, it's out of mind. For this reason, I have trouble using electronic calendars. I have to see data for it to be useful for me; it does not serve me to keep it in RAM, which is very volatile in my brain.
I'm not saying that I only use 3 screens exclusively. My main screen is often my Chromebook, or my Tablet, or the TV with either Roku or Chromecast running. I typically use 3 screens at a time, although not the same 3 screens.
The eReader is surprisingly useful in that it does one thing very well, which is to display printed media. I can email documents to it and have tons of notes available. I could read notes on my tablet too; but, all it takes is one ding to let me know that a message arrived, and i go down the rabbit hole of distraction. Having a reader stay on task helps keep me on task.
For this reason, I think that eReaders are an essential screen in your work arsenal. It can be your file cabinet. The constancy of their display is what makes eReaders a great addition to your workflow.
Bringing Up Star TrekI always wondered why the crew of the Enterprise would deliver reports on a P.A.D.D. to the captain. Why not just email it? I theorize that it is because we need a physical representation of information that is separate from the information product we are creating. And, rather than have 50 tabs open on his browser, the captain could simply have one device dedicated to the task, which he can then return to his officer after completion. Or, it could have been eye candy.
In my experience and opinion, it is much easier to have a reading device, a typing device, and an auxiliary lookup device rather than one do-it-all device. The only exception would be having a computer with three monitors. Considering that today's phones and tablets can do almost anything a computer can do, it seems silly to relegate them to single use devices while you are working. The devices can handle the efficiency-sapping transitions just fine; you do not.