Blizzard brings us a new way to play with our Real ID friends, we can make dungeons and bands with them.
Quote from: Blizzard (Source)
We recently added the ability to form inter-kingdom groups with Real ID friends and now, with Patch 4.3.2, players will be able to use this same functionality to do ancient raids (normal and heroic) and to participate in fields of battle. This will allow you to join real ID friends from other realms and: Create an inter-realm raid and use the Raid Finder. Venture into any classic dungeon or raid, and automatically transport yourself to the same instance. Dominate the battlefields. Please note that you will still not be able to make the Dragon Soul in normal or heroic mode with real ID inter-realm raids. Also, we are looking forward to the arrival of the BattleTag system; yes, they are exciting for World of Warcraft. No matter what realm your friends are in or what realm you are in, they can team up and take on party content from across the game.