Message of the Day (motd) is displayed when you log in with ssh.
You can use plain text message of the day in /etc/motd also in Ubuntu. Disable scripts in /etc/update-motd.d/ to get rid of extra stuff.
When automatically configuring customer systems, it’s a good idea to leave some tangible proof that the systems are configured. Just like a janitor emptying a trash can with just one piece of paper in it.
$ sudoedit /etc/motd
Write some text you want to show on login, then ctrl-X y enter to save.
See you at http://TeroKarvinen.com
Disable Ubuntu scripts that add some cruft to your motd
$ sudo chmod ugo-x /etc/update-motd.d/*
Try it out, log off and then back in
$ ssh tero@example.com See you at http://TeroKarvinen.com tero$
And you should see your motd, and nothing but your motd.