As a whole, since most of the characters share their names with their content creator counterparts, they are differentiated with the character (c!) and content creator (cc!) prefix tags, respectively. This phenomenon has its roots in the Exile Arc (y'know, the Story Arc with child abuse and suicide ideation as a cornerstone), where fans started to add roleplay tags like these to avoid confusion between characters and content creators. Since then, many content creators have adopted this system on social media in reference to their characters, and a similar system is used throughout the MCYT fandom as a whole via fandom overlap and osmosis.
Since CPK's name (or its shortened form) already starts with a "C", he has been addressed as "C!PK" or "C2PK"note short for "c!CPK" in the fandom while his content creator counterpart is sometimes called "CC!PK" or "C3PK"note short for "cc!CPK".
Due to Twitter's character limit, fans on Twitter have taken to removing the exclamation point from the character tag c![X], e.g. c!Ranboo → "cranboo". In response to this particular example, Ranboo the character is often compared with a "cranberry" in some circles.
c!Tommy is often shortened to "Chommy" among his sympathizers, often used to refer to him in an endearing way.
As there are about five characters with some variation of the name "Dream", nicknames and short forms are used to differentiate them and preserve the One-Steve Limit. For anyone not involved in the fandom (or is involved, but is confused), here's a small guide for how the fandom addresses this:
The regular Dream (i.e. the child-abusing master manipulator guy) is just called that, or "c!Dream" as per the character tags above. His content creator counterpart would be cc!Dream, also as per above.
Girl Dream, regular Dream's Distaff Counterpart, is usually known by her El Rapids name "Mamacita". Her content creator counterpart is cc!Dream.
DreamXD the god is usually called by his full name or just XD. His content creator counterpart is also cc!Dream.
Mexican Dream is usually called by his full name or "M.D", an initials-based nickname given by Tommy during the Exile Arc. His content creator counterpart is Quackity (who's Mexican IRL, so there's no issues). Occasionally, some fans call him "Sueño", which is just 'Dream' in Spanish.
Drista's nickname is a portmanteau of 'Dream' and 'sister', and is usually called just that. Her content creator counterpart is technically cc!Drista, but since the Fourth Wall isn't as solid when she's around, she's usually addressed without character or content creator tags.
Several characters on the server have been (usually affectionately) dubbed "whores", most prominently Sam, Wilbur, and Quackity. Phil or even Dream might even get the distinction of being called one if you're 'lucky'. It's at least justified in c!Wilbur and c!Quackity's cases, since the former was apparently called one by his content creator counterpart and the latter Really Gets Around in canon (at least, in comparison with the rest of the SMP), so much that even the content creators joke about it.
The title of the "World's Sluttiest Absent Father" has allegedly gone to either Phil or Wilbur.
Specific characters
Dream is called by a plethora of nicknames, including "Green Boy" (coined by Wilbur in the L'Manburg War for Independence, co-opted by the rest of the server), "Green Blob", "Green Bitch", "Pissbaby", "Green Teletubby", "Homeless Teletubby", and "Homeless Green Teletubby". The second-to-last one and all variations of it are popularized by Technoblade.
Members of the Eggpire are sometimes called "Eggheads", and characters joining the Eggpire and becoming possessed is usually referred to as being "Egged".
Foolish's son Foolish Jr is often shortened to "FJ" or "Junior" for easier differentiation between father and son.
Karl in his colourful blob form/skin is nicknamed "Noodle Karl" (more prominent on Tumblr) and "Gummy Karl" (mainly on Twitter, with endorsement from the content creator himself).
The extended Minecraft–Soot familynote Phil, Wilbur, Fundy, and Yogurt (Fundy's adopted son), and occasionally their respective partners (if any) is sometimes called the "Sootcraft" family, as a portmanteau of the two surnames.
Some fans address Philza as "Peepaw"note Translates to "grandfather" in some parts of the American South or something similar in reference to him being Really 700 Years Old in the roleplay, though admittedly, it appears to apply in a derogatory sense by his critics more often than it does in an affectionate way by his sympathizers.
Quackity gets the affectionate fan nickname of "Quacky" among some of his sympathizers.
Sam is often called "Awesamdad" when it comes to him taking on a paternal role to other members of the server, in a similar vein to Phil and "Dadza".
Tommy has a good few of these all to himself:
Some fans nickname him "Theseus" after Techno compared him to the mythical hero during the Manburg-Pogtopia War.
Especially while living under Techno's floorboards, he is referred to as "RaccoonInnit" for his penchant for stealing from others. This is sometimes cranked up in AU fanworks where he is a raccoon hybrid.
The theoretical ghost version of Tommy is often referred to as "GhostInnit" or "Phantommy".
The many iterations and personas of Wilbur Soot are collectively known as "Bursonas".
The first among these to be popularized is "Vilbur", referring to Wilbur's "villainous" persona during the Pogtopia arc. However, this particular nickname is contested by some fans due to implicated ableism and demonization of mental health problems, while other nicknames for "Bursonas" are typically less controversial. Some fans may opt to use alternative nicknames for Wilbur during this time period, e.g. "Pogbur".
His persona as the President of L'Manburg is sometimes called "L'Manbur".
His persona in the Afterlife is sometimes known as "Voidbur" or "Deadbur".
In AUs where he is resurrected and after his canonical revival, his persona is often nicknamed "Revivedbur", in a similar vein to his canonical living counterpart being called "Alivebur" by his ghostly counterpart Ghostbur.
On Reddit, Wilbur the content creator himself is seen using the nickname "Revivedbur" in a comment about his character, though there are implications that there is a specific context in his use of the nickname.
Michael_Beloved, Tubbo and Ranboo's adopted Zombie Piglin child, is often affectionately called "Mikey B".
Tommy's cat Pussboi — the one that teleported into the prison and was killed by Tommy — is sometimes nicknamed "Hope" by c!Dream apologists because it would forever be 'trapped in Pandora's Vault' as it died there. However, this nickname is controversial in itself due to the controversialviewpoints of c!Dream apologists.
For Tales From the SMP, the unnamed Butler played by Ranboo in "The Masquerade" is often nicknamed "Ranbutler".
Locations
To prevent confusion between the faction called Dream SMP and the server as a whole, the faction is almost universally referred to as the "Greater Dream SMP".
After the Doomsday War, the crater where L'Manburg once stood is usually called either "L'Canyon", "L'Manhole", "L'Crater", or "L'Mancrater".
Wilbur's Personalized Afterlife, being a train station he could never leave and an overall reference to his song "Jubilee Line" from "Your City Gave Me Asthma", is occasionally dubbed "Jubilee Hell" by fans. Alternatives for this name include "Train Hell", "Hellish Train Limbo", etc.
Events
Dream's declaration of war against L'Manburg is usually nicknamed "the 'White Flags' speech", in tribute to its most famous line:
"I wanna see WHITE FLAGS! WHITE FLAGS, OUTSIDE YOUR BASE, BY TOMORROW, AT DAWN, OR YOU AREDEAD!"
The Manburg-Pogtopia War, L'Manburg Civil War, or Second Dream SMP War, whichever one would call it, is often addressed by the date it happened, "November 16th", or as the "Dawn of 16th", after SAD-ist's animatic of the battle.
While multiple characters have been exiled from their countries at different points of time in the server's history, when fans talk about Exile as an event in particular, it will specifically refer to Tommy's Trauma Conga Line of an exile in Logstedshire, streamed during the first half of December 2020.
The events surrounding the Butcher Army and Techno's execution are often called "Hog Hunt", which is, much like "Dawn of 16th", a reference to SAD-ist's animatic of the incident.
The destruction of L'Manburg is universally known as "Doomsday", both by fans and content creators, despite none of the characters referring to it as such, aside from Tommy declaring that it would be doomsday (presumably for L'Manburg) on the day of the Green Festival and that the server had to prepare for it.
The Season 2 finale is most commonly referred to as the Final Disc War or the Disc War Finale, though names like the Disc Confrontation (primarily used on the wiki) and Disc Day are also used.
Others
The Schedule Slip in Seasons 3-4 is often called a "lore drought", especially in comparison with Seasons 1 and 2, where content (at least, from more "plot-relevant characters") came by the day rather than by the month.
The planned reboot announced in mid-August 2022 is generally referred to as "Volume 2" by the fandom, as opposed to "Season 2" as the content creators call it... mainly because in the minds of the fandom, Season 2 already happened from 17th November 2020 to 20th January 2021. For consistency purposes, the reboot will be referred to as "Volume 2" on TV Tropes, as a fan resource.
The tie-in story The Wilbur Van is usually addressed by its Working Title, Hitting on 16, due to the latter being more distinctive, as well as the fact that the title of the fic was initially said to be the latter, but was quickly changed to the former post-publication for unknown reasons.
