[swamp40]

Two spaces after a period just means you learned on a typewriter. I still do it.

[silisili]

I learned on a PC, and we were taught that way initially also. I still think it makes sentences easier to read, so still do it. Though usually on mobile it's .nn because that's where my thumb always wants to land.

[swamp40]

Hah, HN shrunk it down to one space.

[Dove]

Actually, the browser did. Your double space is still there in the page source. :)

(I still do it, too, and mine is also there.)