> Working with Pat Crisman and Louis Pouzin, she also described an early e-mail system called "MAIL" to allow users on the Compatible Time-Sharing System (CTSS) at MIT to send notifications to others about backups of files.[1][5][6] Each user's messages would be added to a local file called "MAIL BOX", which would have a “private” mode so that only the owner could read or delete messages.
I love reading about this kind of feature-of-a-feature that ends up being a huge, industry-wide thing later. It may not have been the full implementation of email, but I'm sure it felt pretty great to get that running at the time.