Community Manager Nethaera hit the official World of Warcraft forums this afternoon to announce a change to guild experience that has been implemented today. Until now, guilds received guild experience for achievements earned. Going forward, this will no longer be the case, and it appears the change is retroactive as well. Any experience previously gained via guild achievements is no more.
We have decided to remove the added bonus of gaining Guild Experience from Guild Achievements earned. This change will realign Guild Achievements with our philosophy held for normal Achievements, which are intended to be predominantly their own reward (barring the rare exception of special achievements that grant an additional reward.) Previously, the experience reward had been seen as an additional side bonus and not something that should have been significantly skewing the advancement of guilds. During the beta, we greatly increased leveling speed across the board and since most characters were copied from templates, guild experience from Achievements didn't seem imbalanced. It has become clear that an imbalance does exist and should be addressed to ensure that guilds progress at the rates expected within the daily Guild Experience limits.
For guilds that are currently above the normally possible experience limit, we will be readjusting it back to the expected limit once more. This will not affect Guild Reputation gains at this point in time.