In response to player feedback, Blizzard has decided to revert the requirement for 'the Exalted' title back to 40 exalted reputations. The team recently bumped it up to 50 reputations in an attempt to keep it a difficult reward in Cataclysm and beyond, but many players were frustrated to lose their title with the change. Blizzard took the constructive posts to heart and will be switching back to 40 reputations through a hotfix or client patch.
If you're wondering why 'the Exalted' title isn't grandfathered like 'the Loremaster' or 'the Explorer' titles, Community Manager Bashiok explained in his post that it's simply a technical issue. While Blizzard can't do it now, they're "working on such a technology that will allow players to keep items or titles associated with achievements even if we decide to change that criteria."
Check out Bashiok's full post after the jump.