The standard Guild Message of the Day is often overlooked by players because it typically scrolls off the viewable chat area due to mods logging information and Blizzard's welcome message. This makes the MOTD a much less effective communication tool than it could be.
This mod pops up a dialog when you first log in to show you the Message of the Day. Click the okay button and it goes away. If the MOTD is changed while you're logged on it will pop up again. If you're in combat when the MOTD changes, the dialog won't appear until combat has ended.
You can also configure it to only pop up when the MOTD has changed and it has (optional) LDB support.
This is a small mod that does a small job well.