Much speculation surrounded the new Alliance race to be introduced in The Burning Crusade, with rumored choices including the Draenei, Centaurs, and Dark Trolls. Even the remaining High Elves were mentioned as a possibility. However, on May 10, 2006, Blizzard announced at E3 that the Draenei would be the new Alliance race in the upcoming expansion. In an interview with Gamespot.com[citation needed], it was revealed that Blizzard chose the Draenei not only for their connection to the Blood Elves and desire to visit Outland, but also because the Alliance lacked a “large” species like the Tauren, and the typical male Draenei is about the same size as a male Tauren.

The Draenei are uncorrupted (as opposed to those led by Akama, as seen in Warcraft III: The Frozen Throne), worship the Holy Light, and are also highly intelligent. Fleeing the shattered realm of Outland after learning of their brothers’ corruption, the Draenei (who travel in an interdimensional ship) crashed in Azeroth on the Azuremyst Isles, northwest of Kalimdor. Azuremyst is the Draenei starting area, and they also have a “Secondary Area” for levels 10-20, which has been named the Bloodmyst Isle. Those that choose to play as the Draenei can play as a Mage, Paladin, Priest, Hunter, Warrior, or Shaman, a class previously only available to the Horde.

Blood Elf racial abilities include:[2]

Mana Tap
Reduces target’s mana by 50 and charges you with Arcane energy for 10 min. This effect stacks up to 3 times. 30-second cooldown. Scales with level.
Arcane Torrent
Silence all enemies within 8 yards for 2 sec. In addition, you gain 10-161 Mana (10 Energy for Rogues) for each Mana Tap charge currently affecting you.
Arcane Affinity
Enchanting skill increased by 10.
Magic Resistance
All resistances increased by 5.

[edit] Classes
For more details on this topic, see Classes in World of Warcraft.
Blood elf characters can play as the following classes:

Hunter
Mage
Paladin (Blood Knight)
Priest
Rogue
Warlock
Though the Warrior class is available to all other races, the Blood Elves never received this, instead getting the Paladin class. Blizzard made this hard-to-decide change during internal testing The Burning Crusade. They chose to “balance out the draenei Shaman class, in exchange for a few other changes.”

The current virtual world consists of two planets; Azeroth and Draenor (a.k.a Outlands). Azeroth consists of two main continents, Eastern Kingdoms and Kalimdor, Azuremyst and Bloodmyst Isles which are located northwest of Kalimdor, and Teldrassil which is also located to the northwest of Kalimdor.

Kalimdor contains the starting areas for Horde races of the Orcs, Trolls, and Tauren. The Alliance Night Elves and Draenei both begin in areas off the coast of Kalimdor (Darnassus and Azuremyst and Bloodmyst Isles respectively), but move to the mainland fairly early. The Eastern Kingdoms contains the beginning areas for the Horde races of the Undead and Blood Elves as well as the Alliance races of the Humans, Dwarves, and Gnomes.

Draenor, added with the release of The Burning Crusade, is only accessible to those who have purchased and activated the expansion pack. It is reached through the Dark Portal in the south of Eastern Kingdoms or through in-game teleportation such as Hearthstones, mage teleports, or engineering devices. Draenor was the original home of the Draenei.

The Wrath of the Lich King expansion will add the continent of Northrend in the northern region of Azeroth and will be available exclusively to those players who purchase and activate that expansion pack.[15]