Structure, not popularity, is how internet communities are best compared

Ask what platform a community is on and you get a brand name, which tells you almost nothing. Ask what shape its container has and you learn how it talks, what it keeps, who can find it, and who can end it.

The shapes are few, the oldest of them predates the web, and the same ones have carried communities under changing brands: Usenet newsgroups, IRC channels, Listserv and GNU Mailman mailing lists, phpBB and Discourse forums, Facebook Groups and subreddits inside a feed, wikis such as Wikipedia, and invite-only Discord servers. Each shape pushes the community inside it a certain way, whether members notice or not.

This page describes the shapes, names the platforms built on them, and sets out what each shape decides on the community's behalf.

What to take away

The five properties

Threading. Whether a reply is attached to what it replies to, so that a conversation can be followed years later, or whether messages arrive in a single stream where the connection between them is in the reader's memory.

Persistence. Whether what was said remains, findable, after the day it was said. This decides whether the community accumulates a record, and the record is most of what the internet culture archives page describes as surviving from any community at all.

Discoverability. Whether an outsider can find the community, and whether they can read it before joining. High discoverability brings growth and the wave that the internet communities page describes; low discoverability keeps the norms intact and the population small.

Moderation tools. What the people enforcing the norms can actually do: remove, mute, restrict, slow, require approval, or nothing. A community's enforcement is bounded by its container's tools.

Ownership. Who can end it. A container run by the members ends when the members choose. A container rented from a host ends when the host chooses, and the host's interests are its own.

The shapes

No row is strong in every column, and that is the point. A community chooses, usually without knowing it is choosing, which properties it will have by which shape it moves into.

What each shape does to the people in it

A threaded forum — a phpBB board, a Discourse forum, a Usenet newsgroup — rewards careful writing and patience, produces a record, and gets slower and more formal as it ages. Its members become writers.

Online chat, from an IRC channel to the chat pane beside a livestream, rewards presence and wit, produces nothing that can be found later, and creates the strongest bonds and the weakest institutions. Its members become friends, and its history is lost. The early social networks page describes the resulting hole in the record.

A mailing list — a Listserv list or a GNU Mailman list — rewards contribution over presence, keeps a complete record in every member's hands, and is nearly impossible for a host to kill, since the record is already distributed. Its members become archivists whether they meant to or not.

A group inside a feed service — a Facebook Group, a subreddit — borrows reach from the host and pays for it with control. The host decides what members see, in what order, and whether the group exists next year. Its members become an audience, which is a different thing from a community and is easily mistaken for one.

A wiki, Wikipedia being the largest, is not a conversation but a shared document, and the community around it is organized by the document's needs. Disputes are about what the page should say, and the history of the page is the history of the argument. Its members become editors, with all that implies about who has the last word.

An invite-only server — a private Discord server or Slack workspace — recovers the small, unfindable, norms-by-example condition of the early web at the cost of any record and any way in. Its members become a circle, and the circle ends when the host does.

Moving between shapes

Communities move, and the move is where the shape's influence becomes visible. A forum community that moves to chat gains liveliness and loses its record within weeks; the long threads that defined it stop being written because there is nowhere to write them.

The move from a public forum to an invite-only Discord server is the familiar recent version. The people come along, the searchable thread does not, and the community's history starts again from the day it arrived.

A chat community that moves to a forum finds the forum cold and empty, because presence, which was the whole experience, is gone. A list that moves into a feed group discovers that its most careful contributors stop posting, because the feed buries anything long.

Standing in the old shape does not transfer either. A forum's most respected writer is nobody in a chat room. The person always present in chat has no forum record to point to.

The reasons are set out under online status and identity: status is issued by the container and denominated in whatever that container counts.

Choosing, when you get to

Common questions

Is there a best shape?

There is a best shape for a given community's priorities, and no shape that is best for all of them. The table is the answer; the brand is not.

Why do communities keep moving to shapes that are worse for them?

Because the move is usually made for reach or convenience, both of which are in the discoverability column, and the costs are in the persistence and ownership columns, which are not felt until later.

Does the brand matter at all?

It matters for who owns the container and what tools they provide, which are two of the five properties. For the other three, the shape decides, and brands come and go under the same shapes.