Insane in the Membrane Going Away with Cataclysm Launch

This revelation happened in their recent Cataclysm Classic blog, where they dedicated a whole header to discussing the removal of the achievement with the Cataclysm launch. Note that this leaves only two faires remaining to finish your Darkmoon Faire reputation.

For reference, you can still earn Insane in the Membrane in Modern WoW, albeit the achievement has received changes to its criteria when compared to Wrath’s version, which includes the removal of the Shen’dralar reputation requirement and increasing the requirement with Bloodsail Buccaneers to Exalted instead of Honored.