I may have mentioned that I’ve spent a lot of time reading and thinking about community, so I’ll point at two books on this I really like before I regurgitate their wisdom. 
I make no claim to my claims.
The issue I keep running into is that “community” is a very colloquial word: people use it to mean a group, an identity, a gathering place, a support network, an audience, a membership boundary, a governed space, a vibe, a set of rituals, a social graph, etc. These things often overlap, but they are not the same thing.
This is where people start talking past each other. We hear “building for communities,” and one person imagines people who have agreed to be in the same place; another is talking about an identity people claim; another is focused on who gets access to a space; then yet another centers the actual feeling of belonging and mutual care, and wonders why everyone else is treating that as secondary.
Some more examples I had written, quoted so you can skip them, or read as food for thoughts:
Communities exist across too many axes, even just inside the atmosphere. You can have communities that form around a single event, seasonal communities, communities around fundamental identities, communities around limited shared experiences like going to the same school, communities trying to accomplish a specific goal, communities that meet regularly, communities where people only appear when they need help, and communities around long-term interests or very tiny fragments of an interest.
Fanworks fandom is a good example of how messy this gets. Someone may at the same time be part of the “fanfiction community,” a specific fandom community, the shipping community inside that fandom, a specific pairing community, a specific interpretation of that pairing, and then maybe a group that got in way too deep and now the pairing exists in a world with no relationship to the original story. Some of those even get book deals, starting the cycle over again! The distinctions may look absurd from the outside, but they are very meaningful from the inside: wars have been fought across these lines, doxxing has happened, countless posts have been created. These groups may talk about the same characters, share some people, share some content, and occasionally want to come together for events like fic exchanges. But that does not mean you can or should collapse them into the same community.
The very beginning of Building Brand Communities (one of the books I mentioned) makes one distinction I find especially useful: a group can share values, identity, and even moral prescriptions without necessarily being a community.
A community, in their framing, requires mutual concern for one another. A list of people with the same background or interest may be a group, but it does not become a community just because the list exists. There is a group of people building for ATProto, but only some of us are here on atprotocol.community, slowly beginning to build relationships with each other.
We don’t have to adopt that exact definition, and it’s not the only one—but I come back to it because it reminds me of why a precise, exhaustive definition of “community” is a fool’s errand.
So the question for me is: how do we do this work if none of us will ever fully define “community”?
The Art of Community has a list (
) that I’ve always taken as a hint toward primitives. Building Brand Communities also distinguishes visitors, participants, and members on top: participation is not automatically membership, and membership usually involves crossing some kind of boundary.
These line up with what others have already said here: @brittanyellich.com pointed at identity, membership, and governance/norms. @zicklag.dev broke out identity, boundaries, authority, and sub-boundaries. @baldemo.to separated community identity, membership boundaries, and social spaces.
Once again, I think people here have more answers than they feel they do—the answers just seem small next to the scale of the space. But we aren’t going to solve “the space,” so we should build in a way that frees us from trying.
Instead of modeling “the community” as one ultimate object, we should focus (as intuition seems to be leading us!) on composable primitives that communities, groups, identities, organizations, and spaces can arrange and rearrange in different ways: identity, participants, members, membership claims, boundaries, roles, spaces, rituals, stories, symbols, inner rings, permissions, and governance/authority.
Getting the composability story right helps with edge cases—let someone else show up with their very particular, very niche needs, and take building a solution for it completely out of our hands. It also speaks to @baldemo.to’s worry about scale: if we’re clear about the separation between identity and governance, between participation and membership, large communities can access the primitives that make sense to them without anyone being able to claim authority.
This last category (the very large, very amorphous community) is a problem space I feel may be currently under-explored. It may be worth having specific discussions about what those communities need, so that we can make sure the primitives we build are not incompatible with them. I definitely have some things I would like to build for the larger fandom community that don’t map neatly into what the current projects seem focused on.
tl;dr: neither the protocol nor us can decide what an atmospheric community is. What counts as a community is unknowable: attempts to pin it down are doomed to end up in fights over competing (and valid) needs. We can only break the problem down, understand its edges, and create pieces that are legible and useful enough, so everyone can come build different, overlapping, deeply weird, and actually useful definitions and experiences on top.
I’m a passionate ATproto advocate, past Atmosphereconf speaker from this year, builder of OpenSocial, and as of just a couple weeks ago an employee at Bluesky! I can’t think of a better or more exciting place to be spending my time and engineering expertise right now than on ATProto.
So with that, please provide your thoughts on that in the comments! I’ll share mine there, too, to not take up any more space here. You’re welcome to participate whether or not you attended of course, and there are no wrong answers here 
it’d be great to understand what you view as a group or community in the Atmosphere and what sorts of examples we have to work from as we get into defining a shared data contract!
) AND book clubs managed through 
Especially this:
