The term pseudo-mailbox is sometimes used to refer to an address that does not correspond to a definitive mail store.
It further exemplifies that some sites may choose to print mail on a printer and deliver the output to the addressee's desk, much like a traditional fax transmission.
The database (file, directory, storage system) in which the client stores the messages is called the local mailbox.
Popular client–server protocols to retrieve messages are: IMAP and webmail can go along with each other more or less seamlessly.
IMAP clients can copy, move, and delete messages in remote mailboxes.
Besides administrative trivia, quota limits help mitigate email bomb attacks.
However, some standardization has resulted in several well-known file formats to allow access to a given mailbox by different computer programs.