I played closed beta and I forget that this was a thing because so many people were using /World to make groups.
Right-click the Chat tab and open up the Chat Settings for Other Channels. From there you can turn on /4 LookingForGroup. Alternatively, you can type /join LookingForGroup when you first login. This is a default Blizzard channel unlike /World that is popular on unofficial servers.
This channel allows you to communicate across zones with players forming groups.
Wasnāt /world world defense?
Iām not sure, but the Defense channel is /3 by default.
I meant to say /4
Because I remember a global defense channel.
/1 General
/2 Trade
/3 Defense (e.g., Ironforge is under attack!)
/4 LookingForGroup
You can change the order of these Chat groups by dragging and dropping them in the Chat Settings UI. For example, you can make /3 LFG and /4 Defense.
Coming from Pservers expect /World to be the general global chat.
I will be advocating to use LFG on my server.
The world channel is terribly annoying because it spams announces when players join/leave the channel.
WorldDefense did exist. I donāt remember seeing it in stress test or beta, but I didnāt remember to check myself when I was in stress test and wasnāt paying attention for it in streams.
It was removed in Legion, so there is a possibility that it was accidentally removed from Classic.
Oh that will suck if the world defense is removed.
The biggest issue with the world channel is it still an unofficial player-made channel, so all it takes is one person to get ownership and lock everyone or just people they donāt like out of it.
Having āworldā be an official global channel would solve both this issue and the one you mentioned without being an intrusive (hell, even noticeable) change.
I might be wrong but I believe you are thinking of āGlobalā. I believe /World is an official chat channel in Vanilla. You just donāt join it automatically. So it doesnāt announce who joins or leaves.
User-created channels have very low limits on how many people can be in the channel.
Either Global or World is an official chat channel in Vanilla. I donāt remember which. One of them is not a āplayermadeā one.
I donāt remember either one ever being an official channel.
I donāt plan on worrying about it in the least. As my partner and I are running a tank/heals pair, all we need to do is find DPS. First opportunity will go to guild members, and only filling the rest of the run from public if needed via chat channels like we did way back in the old days.
I have to say that I never seen anyone use the LFG channel, and I was there since day 1. But I just checked screenshots from launch day 2004 that I took and it was thereā¦then I looked in the strategy guide that was released in 2004 and itās in there too with an explanation for what the channel is forā¦
General is an official chat channel. World is player created.
Iām wrong. World chat was a private server only thing. So LookingForGroup will be the āglobal chatā.
I think thatās because itās not turned on by default. I guess weāre just supposed to discover it. 
channel can be identified as a player made channel quite easily if they have a moderator then its player made if NO moderator then itās a client made channel much like general or trade wich have NO moderators /lookingforgroup is An official channel. however a shorter version known as /lfg is a player channel. the rules differ for player channels. and the penalties are harsher on a Non player channel. to find out if its a playermade tye /chatist (channelname with out the marks) if a players name has * by it. its that they are a moderator and therefore its a playermade. no names with * marks its official.