In a multi-player game, the browser title says "Multi-player - Warlight" and if it's your turn, an asterisk (*) is put in front of it. "*Multi-player - Warlight".
I don't know if it's implemented because I suggested it, but it's one of those little things which make this game a really nice game to play in several tabs in your browser. If it's your turn in any of the tabs, you will notice this.

One thing you will not notice, is someone is chatting with you on public or private chat.
My suggestion: Put a C or P in the title, is a Public Chat (C), or a Private Chat (P) is send.
This is also useful, when more than around 7 players are playing in a FFA game with private chat turned on. You don't notice this, when you don't scroll through the playerlist.
The title could be like this: "*Multi-player - Warlight (CP)" if you have both public and private messages waiting for you.