Merriam-Webster's dictionary entry for the verb gives the military sense: to form or unite into a brigade. [1] For the internet sense you have to go to their editorial writing, where, as it pertains to online voting and user rankings, brigading is described as a large number of users deliberately rating something or voting in a poll so as to create a result that would not have occurred from the usual sample of respondents. [2]
Common use has since stretched well past votes. The sense most people mean now is the one in the summary above: a group arriving together, from somewhere else, because something pointed them here.
What makes it different from a crowd
The distinguishing feature is not the number of people. It is that their arrival was arranged elsewhere, in a place you probably cannot see.
That has two consequences. The first is that the volume does not track anything about your post — it tracks how many people saw the thing that sent them, so there is no relationship between how wrong you were and how much arrives.
The second is that it does not decay the way an ordinary argument does. A thread that got busy on its own runs out of people. A brigade runs out when whatever directed it moves on, which can be considerably later and has nothing to do with you.
Recognising it
- Arrivals with no visible route — people who follow nobody involved
- A burst that starts abruptly rather than building
- Near-identical framing, as though everyone read the same summary of you
- Accounts that engage once and never return to the subject
- Voting or rating movement far out of proportion to the discussion
Every one of these happens innocently. A post can travel far beyond its author's following for entirely ordinary reasons; a large account sharing something brings strangers who were sent by nobody; people repeat each other because there is usually one obvious thing to say. What you can observe is the shape of the arrival, never the instruction behind it — and the instruction is the thing that would make it brigading.
The honest difficulty
You are not in a position to know, and the accusation is easy to make.
From inside a thread, an organised arrival and a post that simply travelled look the same. Both bring strangers, both bring repetition, both feel like being surrounded. The distinguishing fact — that somebody pointed them here — happens in a space you are not in, which means calling it brigading is almost always an inference from what it feels like.
That inference is also convenient. "I'm being brigaded" reframes a lot of people disagreeing as an attack that requires no engagement, and it works whether or not it is true. Anyone who has been widely and publicly wrong has felt the pull of it.
The useful discipline is to describe the shape and stop there: many people arrived at once, saying much the same thing, none of whom were part of this before. That is what you saw. Whether they were sent is a claim about someone else's coordination, and it is not yours to make from where you are standing.
What to do
Reduce volume without destroying the record. Muting a thread, limiting replies or filtering notifications changes what reaches you and leaves the evidence intact.
Do not try to work through it. Replying does not clear a queue that is being refilled from elsewhere, and on most platforms each reply keeps the thread alive.
Report the pattern rather than the messages. A platform can see arrival patterns and account relationships that you cannot, and that is the one place where the invisible part is visible. Where to report, and what a report actually does.
If it does not stop, treat it as organised harassment. A wave that is still going a week later, or that follows you to other platforms, has stopped being an argument that got out of hand and is a different thing wearing the same shape.