In Patch 3.3.5 the new Battle.net Real ID system will be introduced into the game to provide an easier way to communicate friends across any Blizzard game or server. The system has some features like status updates similar to social networking sites. Blizzard's overall goal with the new Battle.net is to create the framework for an online gaming experience that is even more accessible, more engaging, and more entertaining than the previous Battle.net. Their new Real ID feature is an integral part of this effort, providing you with advanced ways for forming and maintaining meaningful relationships with your friends on the service. Real ID is a completely voluntary and optional level of identity that keeps players connected across all of Battle.net. When you and a friend mutually agree to become Real ID friends, you'll have access to a number of additional features that will enrich your social gaming experience in new and exciting ways.

Due to the complexity of the system, Patch 3.3.5 will only be released in North America with all others to follow one week later.

In patch 3.3.5, we will be introducing our new Battle.net system, which opens up new communication options for World of Warcraft players and lays the groundwork for integration with future Blizzard games, such as StarCraft II. In order to ensure that the implementation of this major new system goes as smoothly as possible, we plan to release the patch to North American realms first, with Europe, Korea, and the region of Taiwan following approximately one week afterward. Source - Slorkuz

On top of that, the new Ruby Sanctum raid also won't be released right away.

Due to the fact that we will be delaying the release of patch 3.3.5 in Europe, Korea and Taiwan in order to ensure the patch process in all regions is as smooth as possible, the Ruby Sanctum will not immediately be available on North American realms upon the release of the patch. Once patch 3.3.5 has been released in North America and we are confident about a time when we can open up Ruby Sanctum, we will provide an update here on the forums. Source - Zarhym

The AVR addon will also be purposely broken.

This is a notice that we’re making changes in 3.3.5 in attempts to break the ability for the AVR (Augmented Virtual Reality) mod to continue functioning. For those unaware, this mod allows players to draw in the 3D space of the game world, which can then be shared with others who are also using the mod. In some cases this manifests itself through drawing/tagging/defacing the game world, but more popularly is used to give visual guides for dungeon and raid encounters.

We’re making this change for two reasons. The invasive nature of a mod altering and/or interacting with the game world (virtually or directly) is not intended and not something we will allow. World of Warcraft UI addons are never intended to interact with the game world itself. This is mirrored in our stance and restriction of model and texture alterations. The second reason is that it removes too much player reaction and decision-making while facing dungeon and raid encounters. While some other mods also work to this end, we find that AVR and the act of visualizing strategy within the game world simply goes beyond what we’re willing to allow.

The change we’re making in attempts to break the functionality is light in its touch and approach. When blocking any functionality we run the risk of affecting other mods, but we’ve targeted the changes as carefully as possible. If we find that the AVR mod (or any mod attempting to replicate its functions) are usable after 3.3.5 we will take further, more drastic steps. Source - Bashiok

• The Ruby Sanctum, an all-new 10- and 25-player raid featuring normal and Heroic difficulties, is now available for testing! Players will find the dungeon entrance below Wyrmrest Temple in Dragonblight.
  
• Copied Test Realm characters are not copied with their achievement history in order to better facilitate the character copy process.

• Chat Frame
  
  
  • Players can now right-click on any chat type (Whisper, Trade, General, Party, Raid, etc.) and choose the Pop Out Chat option. This will move that chat type to a separate tab in the Chat frame which can be undocked and moved anywhere on the screen.
    
    
    • Using the Pop Out Chat option on a Whisper will place the conversation with that player in a separate tab.
      
    • Any time a conversation with another player is put into its own tab, the tab will glow when a new message is received.
    
    
  • Hovering over the Chat Frame and using the mouse wheel will allow players to scroll through chat text.
    
  • Players can select Classic Mode under Interface Options to keep the Chat Frame functionality closer to what it was prior to patch 3.3.5.
    
  • The Simple Chat User Interface option has been removed.
  
  
• Friends List
  
  
  • A new icon has been added to the top left of the Chat Frame which will open up the Friends list.
    
  • In addition to its current functionality, the Friends List will now allow players to add Battle.net accounts (Real ID). Players will have to confirm that they are friends in order for a Real ID to be added. Once Real ID friends, players can communicate cross-game, cross-faction and cross-realm.
    
  • A new Pending tab has been added where players can accept or decline a Real ID friend request, or select the Report Spam or Block Communications buttons.
    
  • Players can now select from three statuses which will be visible to their friends: Available, Away and Busy.
    
  • A Broadcast window has been added to the top of the frame. Players can use this to broadcast a message to all of their Real ID friends online. This message will also be displayed under the broadcaster’s Real ID information in each friend’s list.

  Frequently Asked Questions for Real ID