Blizzard is adding a brand new function to World of Warcraft : the ability to undelete characters. The function will be added in a free content patch prior to the launch of their new expansion, Warlords of Draenor .
This is pretty much a first for the MMO world. Usually, character deletion means POOF, all your data is gone. However, Blizzard is willing to house your data on their servers for a short amount of time. Unfortunately, the amount of time that they give you is completely dependent on your character level.
First of all, characters below level 10 are not eligible. When deleted their data is lost forever. Characters between level 10 and 29 will have 90 days to recover their character before the data is lost forever. Characters between level 30 and 49 have a slightly longer period, at 120 days. Any character level 50 and over, on the other hand, is considered a permanent character and can be undeleted at any time.
Even then, players cannot abuse the undelete system. You can only use the undelete option once every thirty days. The option is locked out after you use it, so don’t be careless with your characters. There’s no extra fee for keeping these characters alive anyway.
Undeleted characters come back with no penalty. They have all their enchantments, gems, and items intact. Unfortunately, characters that were deleted before the implementation of this system are not eligible to be undeleted.
Source: Gamespot