I once played an mmo game with a universal chat system.it allows everybody to see someones chat or message.its great for AL since you cant pm somebody when they are offline.your friends,guildmates, etc can then pass the msg to you once youre online.another thing is, its great for auctioning stuff (i know we have the AH and its a way for sts to earn money)but theres a lot of sellers in different servers spamming kraag,elsewhere with their stuff and not everyone can see it and have the equal chance of possibly purchasing it.

you can charge gold for every message (like AH) to avoid spamming.