Account-wide achievements are achievements that can include criteria fulfilled by multiple characters on the same Battle.net account and in the same region.
- Available at the Battle.net account level, as such, would apply to all of the attached World of Warcraft licenses on the account.
- Won't be tied to game licenses. Not sure if these means achievements will count between PTR and Live.
- Intended to be an overall change to the current achievement system.
- Will be available to players without Mists of Pandaria.
- Most achievements will be account-wide.
- Most criteria will not be account-wide.
- Some achievements stay "meta achievements."
- A very few achievements will be account-only.
- Account-only achievements will be those that can't be earned with a single character.
- Plan for rewards granted from achievements (pets, mounts, titles, and tabards) will be shared at the account level.
- Not clear yet how achievements based on reputation will be handled.
WoW Insider Blue Posts: Account-wide achievements to work with non-MoP achievements, "Ask A CDev" soon by Adam Holisky Feb 7th 2012 at 10:30PM