SSH-Terminal: You have new mail

If I log in to my fileserver per SSH, I get the usual MOTD (message of the day) plus a message
saying “You have new mail” (“Sie haben neue Nachrichten”). After some googleing I found out,
that I had to type in the following to see this “mail”:

mail

Very self-explanatory :-P
Then a console mail client appeared on my desk

mail per ssh

You can navigate through your in-box by typing the number of a mail.

By the way: On boot, the server overwrites your MOTD. You can customize this behavior by
editing /etc/motd.tail and /etc/init.d/bootmisc.sh.