By default, the newer versions of Ubuntu (9.04 and up) now auto-edit the MOTD. This annoyed me, so I researched how to stop that, since I prefer my own MOTDs and I’m quite particular about what I am presented with when SSH’ing into a box.
Ubuntu is running an application called “landscape-common”.
More on this application here. The easy thing to do here is to simply type update-motd – -disable and you can then modify your MOTD. Also I have noticed that sometimes, the contents of motd.tail will overwrite the MOTD, so I would simply make sure whatever you want in /etc/motd is also in /etc/motd.tail. [On Debian systems, the system message of the day is rebuilt at each startup. /etc/motd.tail is the file to edit permanent changes to the message of the day].