They did specifically mention the Sami in the article

| Though it may be an unlikely pairing to some palates, among the Sami people of Lapland and other regions around northern Finland, Norway, Sweden, and Russia, sharing a mug of kaffeost is a welcome and welcoming ritual.

I've heard the Sami like salt in the coffee, but the cheese thing is new to me.

My brother's wife is no Sami, just a regular fin, and she, and her mother and sisters, actually use salt in coffee. To me as a regular Swede it's sort of insane.

That sounds odd. I'm a Finn and I can tell you that it's definitely not common here.

Depends on how much salt. Salt just removes some bitterness, it's not too bad. It can actually improve a bad cup of coffee.

Apropos salt in coffee, the way I heard it when growing up was that coffee brewed (or rather boiled) on meltwater didn't quite taste right, add some salt and presto! Having tried that myself I can easily believe that, meltwater doesn't taste the same as well-water. For the record, I tried myself, and yes, when boiling instead of brewing some salt will work, in brewed coffee though, not!