Email still exists, and while this is a travesty in itself, it also offers us the opportunity to look at why you might find yourself interacting with a mail server in your day-to-day job.
Traditionally, servers sometimes ran a series of checks on a nightly or weekly basis before compiling the results into a document and firing it off to the sysadmin, who could then peruse the report and pick up on anomalies or unexpected behavior. Mostly, this is a forgotten art, and very few people ever bother to configure the default mailing location on their system to be anything other than root@localhost.
It's for this reason that you occasionally see you have new mail or a similar notification when you log into a console. The mail in there is usually something that you don't care too much about, from a program that informed you it was...