set this dvar in init() in _rank.gsc (or any other, just make sure it's set in init() )
players will see the original message, until right before the game begins.. maybe if you bind it to a key, so you can set the dvar while in lobby, it might stick & show from the start, i'm still looking for a way to do it from script
SetDvar( "didyouknow", <your message here> );
if anyone has an idea on how to get it to show the entire time the game is loading, let me know