I've had a Stokke Duo for 23 years. Varier is a new name for the company and the Duo is a milder version of Varier Gravity Balans [1]. It's been so good that I just recently had it reupholstered. I've tried Gravity and find it excellent as well. With a nudge you can change between four different positions. The positions are quite stable, it's not like a rocking chair.
I've used IRC since 1988 or so, when all the users were from the University of Oulu, Finland. I hang out in a couple of channels of old pals (in IRCnet) and in a few technical channels in Freenode (#sway, #clojure, occasionally others).
I have a tmuxed session that is always connected, and I attach to it from wherever I happen to be. As others have stated, I too find it a non-intrusive, pleasant way to be in contact with certain groups of people.
Finland has thousands of winter swimmers, just normal people, and Russia at least 10x more. The article makes it sound almost superhuman, whereas in real life it's something that thousands of old ladies do daily. No need to travel to the ends of the world and bring a film crew with you.