Explanations/etymology also appreciated!
For Joe Shmoe, it means a very average or below average person. It’s a derivation of the practice of using “shm-” to dismiss something (eg “Practice shmactice. We’re already perfect”).
And “John Smith” is meant to be the most average name or person imaginable, so they have the “most common” (citation needed) first and last name as well.
In Spain we use “Fulano de Tal”. It seems Fulano comes from the arabic language, meaning “Anybody”. We use it when we don’t the name of a person we are talking about, or we really don’t care to know the name. Apart of Fulano, we also use Mengano.
Fulano/Mengano for men, Fulana/Mengana for women.
I guess our John/Jane Smith would be Pepe/Pepa García.