@scott furthermore, you are failing to account for the following possibilities:

```
id: <post-2>
inReplyTo:
- id: <post-1>
context: <thread-1>
context: <thread-2>
```

```
id: <post-2>
context: <thread-1>
```

```
id: <post-2>
context: [<thread-1>, <thread-2>]
```

```
id: <post-3>
inReplyTo:
- id: <post-1>
context: <thread-1>
- id: <post-2>
context: <thread-2>
```

```
id: <post-3>
inReplyTo: [<post-1>, <post-2>]
context: <thread-2>
```

and many, many more

@scott it feels like you're focusing too much on the issue of "what if something is not a thread?" a la

```
id: <post-2>
context: [<thread-1>, <thread-2>, <not-a-thread>]
```

in which case, you simply drop not-a-thread from consideration.

you also seem to be confusing "object is in a collection" with "object exists in context of something". being part of a collection is not enough.

Here is an example:

id: post 1
context: thread-1, project, flag-a

id: post 2
context: thread-1

id: post 3
context: thread-2, project

id: post 4
context: thread-2, flag-b

id: post 5
context: project, thread-3, flag-a

etc.:

How do I know which one is the conversation that is displayed on the forum?

Here is an example:

id: post 1
context: thread-1, project, flag-a

id: post 2
context: thread-1

id: post 3
context: thread-2, project

id: post 4
context: thread-2, flag-b

id: post 5
context: project, thread-3, flag-a

etc.:

How do I know which one is the conversation that is displayed on the forum?

@infinite love ⴳ Or more specifically, how do I know which is the official moderated version of the conversation according to the forum?

@scott whichever one declares the requisite properties (owned by the forum or some mods on it, scoped to an audience, contains "post" objects bound to a context, etc.) -- if there are any missing properties that you consider "required", then you drop it from consideration.

for example, maybe you consider the "thread" as something special that needs to be declared, e.g. as a ConversationContainer, but i think that's needlessly limiting and not backwards-compatible with unaware implementations.

@scott the core functionality is the grouping of posts by their topic or shared context. the "trick" is that if it's a collection, it's actually entirely up to the owner to decide what goes in there! i could create a collection, declare it to be a ConversationContainer, but then start adding unrelated posts. actually, as the owner, i get to decide what's related and what's not! maybe i require context to be set. maybe i require inReplyTo. maybe i have some other criteria. ideally, i signal this.

@scott so the collection has some "participation criteria" which describes the shape of what i deem worthy of potentially Adding. for example, i could say that
- object.content must be present
- object.attributedTo must be present and included in the Collection.audience
- object.context must include Collection.id

but this is advisory at best. i reserve the right to add objects that don't match this shape.

i also can hint how i think the collection should be displayed, but this is only a hint.

@scott the point i'm trying to make here is that, in an open world system, there are limits on what you can enforce or expect. it's always possible that you will encounter something that breaks your expectations, so make as few expectations/assumptions as possible.

the idea of a "thread", when broken down to its core semantic ingredients, is not significantly different than "a group of posts bound by some common key characteristic". structure is created within that grouping.

@infinite love ⴳ You also have to consider that most systems may get duplicate versions of the same post from different sources.

For example, if I am following someone and following the forum, I will be sent one copy from the person I am following, and one copy from the forum. The forum will have a context attributed to the thread, and the other version will not.

Since the forum sends a copy of all of the posts in the thread directly to followers of the forum, you don't even need to process the reply tree. Just look for the context that indicates the thread and show all posts marked with that context. Any post without that context has been moderated out of that thread.

If you want to utilize the moderators of the remote system, you have to display only what they approved to be in the thread. If you don't care what the moderators on that other system think, you process the reply tree instead, and only use the context to backfill the conversation.

To minimize spammers and trolls, you drop any post that does not belong to that context (the moderated forum thread) and/or does not belong to someone you follow.

You don't have to do that and can let anything in the reply tree through, but if someone is already moderating a thread, that's less work for me.

@scott
> The forum will have a context attributed to the thread, and the other version will not.

The forum doesn't have permission to modify the author's post. It can only send an Add and/or Announce.

Instead, any consumer wanting the "moderated version" needs to either fetch a collection's items directly, or establish proof that any item was Added to the collection. If you can't prove this, you hide or drop the post as "unverified".

This continues to have nothing to do with reply trees.

@infinite love ⴳ And this continues to have nothing to do with threads.

You are so wrapped up in reply trees that you refuse to acknowledge that threads are a distinct type of list.

And based on some of your comments, I get the distinct impression that you are actually against the idea of having threads. Or that you have never used usenet, email, forums, Facebook, or any other platform that uses threaded conversations. But I will give you the benefit of the doubt and assume you just are against the idea of threads.

Yes, you can get the whole (or most) of conversation from the reply tree. We know that. That is how most platforms do it today.

I want to know what the thread is (the moderated version of the conversation) for different reasons, which I have stated over and over.

So, I will simply chalk up your refusal to acknowledge threads as being a valid way to organize and moderate conversations as a philosophical stance.

If so, I will respect that. But don't expect other platforms to think like you do.

Because everything you have stated is consistent with Mastodon, not forums nor threaded conversations. And the way you want to implement things ignores some of the main benefits of having moderated forum communities.

@scott It’s *the web*, not Mastodon. I’m not opposed to threads, I’m just saying that they necessarily work differently when you have resources split across multiple authorities. Post owners own their posts on their own domain. Posts can *claim* to have been created in a certain context, but unless you reify that context as a collection with items, you have no authoritative origin to check for what officially got added. The problem is in Mastodon et al *never checking any collections*.

@scott Even with reply trees, Mastodon et al will only ever use inReplyTo. They ignore the “replies” collection. This bypasses the authority of every post author to get to decide which responses they want to acknowledge and which ones they don’t. The other issue is that they don’t recognize a “conversation” or “context” as an actually existing reified object. At best, it’s an opaque string hint that you can search your database for and reduce your search space for a reply tree.

@scott So the way forward is to:
- recognize the concept of a “conversation” or “conversational context”
- start declaring that posts are not standalone and that they exist in some “context”
- reify that “context” as a collection that has canonical items
- give the context collection an “owner” or “moderator” who chooses what goes in and to whom you can send objects for consideration
- stop taking post metadata at face value and actually verify the information you’re trying to present to users

@scott but in all of this, you have some invariants:

- the post owner owns the post
- the collection owner owns the collection
- any collection may contain any post, without it being a context
- context is something that the post author “declares”; the collection owner “fulfills” this declaration by adding the post to the canonical collection representing the conversational context
- a third party browser/consumer/processor cannot assume that an object is contained in a collection it implies.

@scott For example, “inReplyTo” does not imply membership in any “inReplyTo.replies.items” if present. “context” does not imply membership in any “context.items” if present.

If the post exists in one or more contexts, then for most intents and purposes you can ignore the post and navigate away from the post and to any one of those contexts; if it is an OrderedCollection, you can render its items in a flat list by whatever canonical ordering is provided for you.

@scott But the way you render that OrderedCollection as a flat list is actually not as important as you’d think. In that sense, there is no significant difference between rendering it in the UI of social media, or of forums, or of messengers or chat rooms, or of something else entirely. At the end of the day, it’s a flat list of posts in a given order. The collection owner can hint to what they *intend* it to be, by declaring a type like ConversationContainer or TwitterMoment or whatever else.

@scott In this case, ConversationContainer might define that the collection owner is expecting you to send posts to them to be added; TwitterMoment might define that the collection owner is just curating some posts they found interesting, and that they will not be considering any posts you send them.

In the absence of a “send” or “don’t send” signal, we generally assume “send” if the context resolves to a collection with an owner and that collection does indeed contain the post (“verified”)

@scott but here’s the thing: by definition, it is generally invalid to declare a TwitterMoment as your “context”, because in reality you are not creating your post only to be considered as part of that TwitterMoment. So in most practical cases, you can generally assume that any context collection is in fact sufficiently considered a “conversational context”. Most contexts are multi-faceted in this way. https://w3id.org/fep/7888#the-different-types-of-context-and-how-they-are-actually-the-same

@infinite love ⴳ

Most contexts are multi-faceted in this way. #^https://w3id.org/fep/7888#the-different-types-of-context-and-how-they-are-actually-the-same

Yes they are. But, as I said, there are practical reasons for wanting to retrieve the conversation container (forum thread, social media thread, chat thread, etc.) as opposed to the reply tree.

The biggest practical reason is delegation of moderation. In order to limit spam, trolls, and off-topic discussions, the owner(s) of the conversation container (thread) will moderate content by removing it from the conversation container, moving it to another conversation container, or flagging it in some way.

If @julian spots a spam post on NodeBB, he can delete it. And if I retrieve the conversation container (thread) that NodeBB places the posts in, I will get the moderated version of the thread without the spam. If I parse the reply tree, I get the spam even though Julian deleted it.

It also helps keep conversations together when the forum moderator moves a post to a different thread. If you follow the reply tree, the post would appear in the wrong thread.

If you want threaded discussions to behave like threaded discussions over ActivityPub, you need to provide additional information that allows that to happen.

cc: @Evan Prodromou