EU players have apparently been seeing some pretty massive queues... however Blizzard have assured everyone they are keep a close eye on it.

Due to first the 2.3 patch and now the start of Arena Season 3, the World of Warcraft realms are experiencing increased activity especially at peak playing hours. On a few realms this has resulted in (extended) queues, delaying players' entry to the particular realms.

Be assured that we're closely monitoring these queues and the population trend on all realms. However, due to the feedback we've seen from players in the past, we do not wish to take any knee jerk reaction on what may very well be a temporary issue. Should the queues persist we will come back to you on the issue. 

Why Blizzard don't open new relams when people want a fresh start:

We will let this thread open for discussion for now since you asked so nicely, but please note that new realms are only opened when there is an actual need for them. The decision of whether or not there is a need for new realms is solely based on the population on existing realms and expected population increase in the time ahead.

We realize that there is something attractive about being on a brand new realm where everyone is just starting out, but we simply cannot open a new realm because of "popular request" whenever someone feel like starting over from a fresh. If this was to be a factor when considering new realms, we would need to open new realms every month resulting in a large number of very empty realms, which is something that is far from desirable.

Is your realm low pop - do you want help from Blizz? Well they are working on it:

We're in the process of implementing alternate solutions to help assist the lower population realms. The problem here is that Agamaggan is not really what would be considered a "low population" realm, it's not even in the bottom 25 realms. While it's not at capacity (it's at around a 55% nightly pop) there are quite a few realms below it that we would need to focus our attention on first, such as Coilfang (around a 30% nightly pop) and 10 or so other realms like it.

Just to compare there are technically around 200 realms that aren't actually hitting capacity (no queues at any time for a month+) out of about 220 total US realms. While we would like all realms to be near capacity, there is a middle ground that still allows an extremely functional and fun play experience. A lot of the realms live in this "middle area" of capacity, and they have extremely lively economies and interactions. Before the population cap increase with Burning Crusade they might even be considered "high population".

In any case, when realms fall below that middle ground, which Agamaggan has not, then we need to start taking some action.

Our focus is going to be on those realms that are falling below a capacity we believe is acceptable to the players, and our intent for the ability to play the game with any amount of comfort. After that we would then continue to move up and focus on other realms.

Some realms have low pops and there is really nothing that Blizzard can do about it... so why not merge realms together people are saying.

We're certainly looking at additional means to help realms that have lower populations.

There are a couple issues with merging realms though that we would need to take into heavy consideration if one were to be considered. As many of the lower population realms are PvP, faction balance has to be taken into careful consideration. Would a merge worsen, improve, or leave any faction balance unchanged? Would a merge move the population up too high, queuing or leading to queues for the realm after that point? Do we have realms of the same time zone and type that would merge well under these conditions? There also many logistical issues with merges which ultimately effect the end user, such as conflicting character and guild names. So, in the end, a merge would only be considered if all other possible options have been completely exhausted.

We're not just throwing recommended tags up on realms, and calling it a day. The recommended tag has done a lot of good for a lot of realms, but if we're seeing that they're no longer helping reach the type of population numbers we would like to see, then we would investigate alternate means. That's sort of where we're at now.

There was a realm crashing exploit going around earlier... however it appears that Blizzard might have also just patched them with rolling restarts.

Before you ask, no, I'm not going to reveal how to crash a realm in just a few simple steps. It would be chaos. However, there is, in fact, just such a technique making the rounds of the internet. Hopefully it will be fixed very soon -- one commenter I've seen says that his realm went down four times in 20 minutes. I'd say that qualifies as a serious problem. If you've been having realm stability issues lately, perhaps some jerks performing this exploit are to blame. And Blizzard? Please get this fixed ASAP.

34 Realms are coming down for 2 days straight next week!!!

Aggramar, Argent Dawn, Arthas, Azgalor, Bleeding Hollow, Bloodhoof, Burning Blade, Burning Legion, Durotan, Earthen Ring, Elune, Eonar, Eredar, Gilneas, Gorefiend, Kargath, Laughing Skull, Lihgning's Blade, Llane, Lothar, Madoran, Magtheridon, Malygos, Mannoroth, Medivh, Shadowmoon, Shattered Hand, Skullcrusher, Stormrage, Thunderhorn, Thunderlord, Trollbane, Warsong, Zul'jin

That hurts!

I didn't notice myself, but here's a return to the days of old. Apparently some relams were down for an extended period earlier today.

We're aware the below realms are currently down and our network engineers are working to bring them back up as soon as possible. We're currently estimating we will be able to begin bringing them back up in approximately 30 minutes, and we'll provide an update at that time. 

Hoping for a new realm to turn up so you can reroll or start fresh? Don't hold your breath...

We have no plans to open new realms at this time. It is always under consideration and we will let you know when we feel it is appropriate to open new realms. 

Could 5 new realms be coming soon? Apparently they are listed in the realms list in-game, but can not be selected to play on. Drysc points out it's an error:

    legion hold <pvp>
    halaa <pvp>
    ghostlands <pve>
    eversong <pvp>
    bladespire <pve>

Thank you, I'll ensure those are removed as well.

Apparently Blizzard are still working on realm stability issues, although I must say I haven't noticed anything wrong!

Blizzard poster Crezax has just posted an update saying that yesterday's World of Warcraft patch not only implemented several content updates and bug fixes, it also "implemented some background tweaks to specifically improve stability across all realms and especially instances."

The following English realms will open at TBC launch approximately 00:01 on the 16th of January:

Normal (PvE)
Hellfire
Ghostlands
Nagrand

RP
The Sha'tar

PvP
Auchindoun
Karazhan
Shattered Halls

RP PvP
Sporeggar

Battlegroup
All these realms will be together in a new Battlegroup. Name yet to be released.

All these realms will be no-migration realms, and thus will not see players transferring to them until the PCT allows such when the realms are 6 months old.