The full post from Wryxian reads as follows:
Recently there has been a number of extended maintenance periods for certain realms. Some of these we informed you about in advance and some we were unable to until during the actual maintenance period. We want to take the time to explain the reasoning behind these extended maintenance periods, and also those that will need to occur in the future.
These extended maintenances are directly linked to the message we posted in early July (http://forums.wow-europe.com/thread.html?topicId=9941934722) about our investigations in regard to instance capacity and our plans to implement hardware modifications to achieve positive change for your play experience. As we said we would do in that message, we are now informing and updating you of our progress.
These modifications are typically a two stage process, requiring two lots of extended maintenance for each group of realms being worked on. For the realms listed below, the first stage was completed successfully on Wednesday the 15th of July during a pre-announced extended maintenance period.
On Wednesday the 22nd of July we also began to complete the second and final stage of this process on the affected realms. However, we encountered unforeseen difficulties in implementing the modifications. We were left with two options; either to further extend the maintenance period well into the evening and thus the busiest playing hours, or to take just a couple of extra hours to roll back the changes so that the realms could be back up and playable quickly. Since we did not want to disrupt your ability to play the game during the prime time, we decided on the latter option.
Since the final stage of these modifications did not complete successfully, we will need to do a further extended maintenance for the realms listed below. This is currently planned for the next maintenance period on Wednesday 29th of July. Because of this, we wish to inform you in advance that the realms listed below will again experience extended maintenance as we implement changes that we believe will bring positive change for your play experience, especially in regards to the ability to enter dungeon and raid instances.
After these modifications are implemented successfully, we aim to post up a feedback thread so that you can share with us your thoughts on how they have affected your play experience. At that stage, we will greatly appreciate it if you are able to help us with your feedback.