I resubbed after a hiatus and I’m trying to find a new realm. After testing a few, I’m seeing players from realms that are not connected according to the Blizzard support page.
Why am I seeing those players in capital cities? Can I join guilds from one of those other realms? Is raiding/mythic progress tied together?
It is part of some newer tech. Basically if a sever is lower pop at a time, it can get folks from other realms. They try to keep it to the same realm type so no RP and Normal realms mix. Just doesn’t happen all the time.
It’s Cross-Realm Zoning (CRZ). Was new, not anymore. Continuing to annoy people every day. So that rare you want on a dead server? Might not be so dead.
It can be a pain when making a bank guild. You have people who wish to help but can’t because they aren’t on a connected realm.
Ok so cross-realm zones are basically just there so you don’t feel so lonely? Auction house and guilds are still separate and contained within their own server or connected realms then?
I just recently came back to the game after a year+ break. The auction house is connected across all realms now.
Guilds can have members from connected realms.
I’m on Icecrown. Before my break we were linked to malygos. We have apparently merged with garona and which ever realm they were linked with.
Because the world is too empty so it has to be artificially populated with crz
Even on stormrage (largest alliance server) if i go to elwynn forest half the people in goldshire are from random non stormrage servers
The only servers that are free from that are rp servers as those only shard with other rp realms
Auction houses are cross realm now for consumables/utilities. Other than armour and pets, most things on the auction house are shared. Horde and alliance have had shared auctions for a while too
You can only join guilds from your connected cluster
A Connected realm is only useful at the current time for a guild, being able to trade, and for raiding mythic within the first 2 months of a raid tier.
The entire rest of the game, including Communities, is cross realm.
Even the AH is cross realm.
So everyone you see is a potential player you can group up with and do any content with.
“Servers” don’t have a lot of meaning, the whole game can be played together across all servers.
I think CRZ was annoying when you couldn’t interact with those people ever again.
Now everyone you see or meet out in the world you can friend and play the whole game together with them.
It has been this way for a long time. How long have you been gone?
Unless they are members of the other faction.
Well, that’s always been the case in this game and right now is the closest to being able to group with a member of the opposite faction as it’s ever been with being able to group for dungeons and raids.
Faction tagging should no longer be a thing. If there’s only two of us in a zone, and one is of the other faction, we should be able to work together, rather than each solo elites.
Because the current dev and management teams have chased away so many players that we have to have cross realm zoning so people can actually get groups.
Semper Fi! 
The reason CRZ was put in so many years ago is that a lot of realms were already dead.
I found it somewhat relieving, aside from the input lag/delay I experience when in parties with Oceanic players.
It isn’t CRZ, CRZ is the old system.
It’s a new system called sharding. Basically realms don’t really exist in the same way they used to. Your realm/connected realms is just a login portal and half the auction house now.
How it works is the game will create an instance or “shard” of a zone. It will then fill that shard with anyone from a given timezone and when that shard fills up it will create a new one and start filling it. Then should old shards population fluctuate they will dynamically merge or split them.
You can see this in action when you get events where large groups congregate. You will see large numbers of people just suddenly disappear or appear out of nowhere. It got really bad back in BfA on Mechagon at the spawn points for the rares that dropped mounts.