SpuriousZabaione said:
From a tropical island pov, it's either you have met them first in person before they went somewhere far away or you get introduced to them by a colleague. Mail penpals was a/the common way to keep in touch back then esp. before telephony (most esp. the overseas one) became common and dirt cheap in the tropics.

hmm... I guess that living in a really big city with, like, zero tourism has probably skewed how I've viewed stuff like this. probably not helped by my sort of putty-like social skills.