I don't get it...
Basicly, as seen in other games, every however minutes (You choose) it will display a server message, a different one every time, and you get to chose them. You can choose up to 10 messages.
For Example:
Be nice to other players.
*Whateverminuteslater*
Follow the Rules!
It can be useful for some things, Like in a TDM, You could have one say: "Work together as a team!" Or something like that.