Where do people learn these things?

A phone conversation I had a few minutes ago (with the names changed, obviously):

"Hello, could you give me Ron Klein's email address, please?"

"It's Ron dot Klein at Percival dot com."

"Is that the wee 'at' symbol?"

"Sorry?"

"Is that the wee 'at' symbol or A-T, the word 'at'?"

"It's the 'at' symbol; it's an email address."

"Oh, yes, I know; it's just that a lot of them are using the actual word A-T now."