I've updated the code once it for all and decided to save every message sent and received from/to another player.
If you wish to change the appearance of the motd window you could so to at line #36
There will not be an option to message offline users or admins, there are plenty of other options such as report systems or even texting admins on other platforms, steam etc.
Consider criticizing/improving and updating the source and leaving feedback. Always up to recommendations to a reasonable extent.