Everything needed for the cross-realm Dungeon Finder and Raid Finder features is now implemented, which now essentially means the following.
You can invite players from other realms with his realm's name, this looks like below:
And why is this good now? Because you can queue Random BGs and arenas with players from other realms, which is actually something we really would like you to do, since it's a great deal of help for us when it comes to testing the cross-realm system's stability. If we deem the system stable enough, we'll implement the cross-realm Dungeon Finder and Raid Finder features.
At the same time, cross-realm whispers have received a breeze of redesign. Instead of 'Player.Realm' you'll have to use 'Player-Realm' whenever you'd like to whisper to players on other realms.
And since it's going to be actual fairly soon, here are a few pieces of information about the MoP launch:
Have a great time!