Many computer systems display a message of the day or welcome message when a user first connects to them, logs in to them, or starts them. It is a way of sending a common message to all users, and may include information about system changes, system availability, and so on. More recently, systems have displayed personalized messages of the day.

On many time-sharing systems, the contents of the message of the day are fetched from a system file:

• Compatible Time-Sharing System;^[1]
• Multics: the motd info segment;^[2][3]
• TOPS-10^[3]
• Incompatible Timesharing System (ITS)^[3]
• Unix-like systems: the /etc/motd file, though most modern Linux distributions do not support the /etc/motd file.^{[citation needed]}
• Univac VS/9^[4]
• CP/CMS^[5]

The contents of the special file are displayed after the user logs in successfully, typically before the login shell is started.^[6]

Newer Unix-like systems may generate the message dynamically when the host boots or a user logs in.^[7]

Various server-based PC games display messages of the day, including Half-Life, Call of Duty, Minecraft, and Battlefield. They may be personalized, encouraging users to try new features or make in-game purchases.^[8]

Some IRC servers also display a message of the day on login.^[9]

• System console
• Fortune_(Unix)