Really. This isn't a magic trick.
And I can vouch for this one because I tried it -- and was able to duplicate it time after after time. Now, this video only shows folding t-shirts and works on sport shirts, as well, butt as you see below it, apparently works on longsleeve shirt, too. (Though this would take more than two seconds, since you'd have to button it up.)
But this is quite remarkable. I say that because, among other things, I am not a good shirt folder. I've been taught, repeatedly and I try hard, and come close, but...no go. It's always a bit sloppy. Most especially with longsleeve shirts. (Admittedly, sports shirts and t-shirts aren't nearly as difficult, but even there it's always taken me far longer than two seconds.) But now, particularly with sport shirts, this not only works near perfectly, but...in two seconds.
(Okay, disclaimer: I don't feel as confident with it yet as the Lifehacker guy blithely flipping the shirt through the air, so it takes me more than two seconds. But it's still only about 4-seconds.)
I did try it several times with a longsleeve shirt, and actually came close. I haven't figured out how to pull that off properly yet -- my results were not nearly as department-store smooth as this picture -- but it was semi-reasonable enough that I might use it when next packing.
Watching this video and then practicing will make you anxious for it to be laundry day...!