With JB’s permission, it’d be pretty cool to have a dedicated thread to the topic, “Today I Learned.” I find this forum to be one of the more interesting repositories of random factoids. Perhaps there’d be an interest in others sharing their own, barring any which rely on links to Wikipedia? 

It seems that with the advances in communication technology over the past few decades, "OK" has become universal.  No longer a new word that people learn when coming to the USA.