In completely unsurprising news, extended maintenance for the realms that were undergoing it has been additionally extended today. These realms were suppose to be brought up at noon PDT today. The latest news is that there is no current ETA for them to come back, but that we should get another update by 1 PM PDT (at which time I fully anticipate they will tell us to expect another update by 2 PM PDT). The good news is they're doing hardware upgrades, so when the realms come back up, they should be better than before.
The affected realms are: Aegwynn, Akama, Aman'Thul, Arathor, Azjol-Nerub, Barthilas, Blackrock, Bloodscalp, Bonechewer, Boulderfist, Bronzebeard, Caelestrasz, Chromaggus, Crushridge, Daggerspine, Darkspear, Dath'Remar, Draenor, Dragonblight, Dragonmaw, Draka, Drak'thul, Dreadmaul, Dunemaul, Eitrigg, Eldre'Thalas, Feathermoon, Firetree, Frostmane, Frostmourne, Frostwolf, Garithos, Gundrak, Gurubashi, Hakkar, Jubei'Thos, Khaz Modan, Khaz'goroth, Kil'jaeden, Kilrogg, Korgath, Kul Tiras, Malorne, Mug'thol, Muradin, Nagrand, Nathrezim, Ner'zhul, Perenolde, Proudmoore, Rexxar, Runetotem, Saurfang, Scarlet Crusade, Sen'jin, Shadow Council, Shadowsong, Silver Hand, Silvermoon, Skywall, Smolderthorn, Spirestone, Stonemaul, Stormscale, Suramar, Terenas, Thaurissan, Thorium Brotherhood, Tichondrius, Uldum, Vek'nilash, and Windrunner. All other realms should be available for play now.
We will keep you posted as soon as we hear more on when the realms in question will be brought up.
Update: As predicted, they have updated to let us know that they still don't know when these realms will be back up, and they will have another update for us at 2 PDT.
Update 2: Blizzard has announced that they expect these realms to be available for play by 2:30 PDT.