What would cross-posting between instances look like in ActivityPub?

[rimu@piefed.social]

IMO The simplest way would be to garnish a bit of extra data onto the normal FEP 1b12 process.

Create a new post (Create -> Page to the instance that hosts the community, which in turn does Announce -> Create -> Page to followers) and add an extra field to the Page which is the URL of the original post. That will establish the association.

To reject the cross-post, return HTTP 400 (403?) to the POST to the inbox on the initial Create -> Page ? Or send a Reject activity, either way is fine but the 400 seems easiest. Lemmy returns 400 for a lot of things, PieFed just blindly accepts everything.

[jdp23@socialhub.activitypub.rocks]

gunchleoc:

Mastodon is currently working on a spec for their groups implementation.

Any links to this and/or discussion of how it relates to other FEPs?

[Gæst]

Duplicating the object would mean the discussion is split between objects. The ideal implementation would be the same object present in multiple categories/communities. Is there desire for this in the threadiverse?

If the link goes to a controversial news article and it’s get posted into pro- and against- community/group the comments will spiral out of control and it won’t be a pleasant place.

Maybe it could be implemented as a toggle per group/instance within one fedi software. It shouldn’t be in Activity Pub protocol.

[Gæst]

https://github.com/mastodon/mastodon/pull/19059

[jdp23@socialhub.activitypub.rocks]

THanks ... turns out I knew about that: the implementation for the NLNet grant, but never released. My impression is that it's been on hold since then, and there's so much other discussions of group-releated FEPs that I certainly hope they'll incorporate newer thinking if and when it moves forward.

[julian@community.nodebb.org]

I haven’t looked into the differences between their implementation and how groups are implemented using 1b12, but what I have discovered is that the 1b12 community is much larger than I gave it credit for.

[projectmoon@forum.agnos.is]

How would this work on the NodeBB side? Multiple categories associated with one topic?

[julian@community.nodebb.org]

projectmoon@forum.agnos.is basically, yes. It would be a little too involved to upend the entire system to support multiple cids per topic — a lot of our existing code relies on cid being a single value.

This would be an add-on logic of sorts, where each topic has a canonical category, but can also be cross-posted to other communities/categories.

[julian@community.nodebb.org]

Hey rimu@piefed.social thanks for responding (and sorry for the late reply!)

I am not married to the Announce([Article|Note|Page]) approach, so I am definitely open to Create([Article|Note|Page]) with a back-reference. I think I went the former direction because there is a known fallback mechanism — the Announce is treated as a share/boost/repost as normal. However, sending the Create also is fine I think.

1. However, do we need a backreference? In my limited research, it seems that Piefed, et al. picks the first Group actor and associates the post with that community. If I sent over a Create(Article) with two Group actors addressed, could Piefed associate the post with the first, and initiate a cross-post with the remaining Group actors?
2. Secondly, is how to handle sync. 1b12 relies on communities having reciprocal followers in order for two-way synchronization to be established. On my end since I know it is cross-posted I will now send 1b12 activities to cross-posted communities, but can Piefed, et al. send 1b12 activities back as well, in the absence of followers?

cc andrew_s@piefed.social nutomic@lemmy.ml melroy@kbin.melroy.org bentigorlich@gehirneimer.de

[silverpill@mitra.social]

@julian Hi, what's the status of this? Is cross-posting still done by making a copy of a post?

[julian@activitypub.space]

It was noted that there were some social barriers that would be crossed if federated cross-posting were implemented.

Namely, tribalism exists in all corners of the fediverse (related; see Jaz’ “million fediverses” blog post). It is more pronounced in the threadiverse because there are explicit fences around communities, e.g. sports team, political leanings, etc.

There is the potential for abuse to occur if cross-posting were made available to users. e.g. enabling dogpiling by cross-posting to a community who does not share the values of the original post.

In and of itself that’s not a reason to not move forward with this. I went ahead and implemented cross-posting in NodeBB itself, but only locally. That is, remote posts can be cross-posted to local categories, but not the other way around. It’s worth noting that me doing this already enables the dogpiling behaviour, though NodeBB forums in general aren’t really all that tribalistic so in practice there have been no issues.

As far as I know, Piefed and Lemmy still treat cross-posts as separate entities. However, they both have independent implementations where similar posts (those that have the same Link, I think) are “linked” in a manner of sorts. Browsing the comments of one post would show comments from similar posts across different communities.

NodeBB does not do this because we do not group content together by Link.