Phase Two of the Starcraft II Beta was launched today.
The recent debate over Real ID is still open for discussion, however the new character code has been introduced in Patch 16, the opening patch for the just-launched Phase 2. A character code is a unique code tied to your SC2 character. It is created when you create your character and cannot be changed nor chosen by you.
On the Battle.net forums, this post by Zarhym details what Patch 16 brings to Starcraft II. The 'General' patch information:
StarCraft II Beta – Patch 16 (version 0.19.0.15976) General Rally points now behave as a move command, instead of an attack move command. Enabled the ability to manually add a StarCraft II character friend using the player's character code. - Character code is a server-assigned numerical code that is displayed within the Add Friend panel. Battle.net Achievements & Rewards have been updated. All Quick Match modes are now available: 1v1, 2v2, 3v3, 4v4, and Free For All. All A.I. difficulties are now available for play. Cooperative matchmaking versus A.I. players is now available as a play mode. Enabled cross-game social features between World of Warcraft and StarCraft II.
More details about Patch 16 can be found on the Battle.net forums or by clicking the link provided earlier.
Also keep in mind that Starcraft II will be released on July 27th, 2010.