Yes, a Delete activity is sent to all instances with actors that follow the category/community. Those instances then delete their local copy. In Lemmy/PieFed there is no distinction between deletion and removal.
The deletes are soft so it is possible to un-delete by sending an Undo activity. PieFed keeps soft-deleted posts (topics, in NodeBB language) for a few days then after a week deletes the content from the database.
All of these activities are enclosed in an `Announce` and the http POST is signed using the community key. So in a way the content 'belongs' to the community, not to the original author. With that model of ownership the idea of removal redundant - a post without a community is not a post.
Tangentially - it would be good to come up with a way to move a topic to another category and federate that so the move can happen on other instances, too. We could go off-piste and create a `Move` activity, or use `Remove` (from old topic/comm) followed by `Add` (to new topic/comm) to do the same thing. I feel more inclined to go with `Move` as it's a single atomic operation that either succeeds or fails, despite it not being in the spec.
The AP spec is so badly stretched by various implementation-specific differences that I don't think it's worth being ideological about adherence to it it anymore.
Rimu
npub1dj…ux0zv
2025-09-06 22:53:09 UTC
in reply to nevent1q…j686
Author Public Key
npub1dje7m375wqzmdjzy5et5w7qj925yn9yyvmynctflq2mjr94emf9q0ux0zvSeen on
wss://relay.momostr.pinkPublished at
2025-09-06 22:53:09 UTCEvent JSON
{
"id": "deef0078aa9dad12e3c86817c8ed91469089b52b62b63540e835bb81723d64e0",
"pubkey": "6cb3edc7d47005b6c844a6574778122aa849948466c93c2d3f02b72196b9da4a",
"created_at": 1757199189,
"kind": 1,
"tags": [
[
"p",
"6cb3edc7d47005b6c844a6574778122aa849948466c93c2d3f02b72196b9da4a"
],
[
"p",
"dfec30efc51cbeffc045bde468c9f3d43c4f80964bb74046d894ea43d895946e"
],
[
"e",
"6aecdf2d8e0a6e3cd40777f716ef7c8c9451803eeafc06c469690a3c7f44c001",
"",
"root",
"dfec30efc51cbeffc045bde468c9f3d43c4f80964bb74046d894ea43d895946e"
],
[
"proxy",
"https://piefed.social/comment/7863568",
"activitypub"
],
[
"L",
"pink.momostr"
],
[
"l",
"pink.momostr.activitypub:https://piefed.social/comment/7863568",
"pink.momostr"
],
[
"-"
]
],
"content": "Yes, a Delete activity is sent to all instances with actors that follow the category/community. Those instances then delete their local copy. In Lemmy/PieFed there is no distinction between deletion and removal. \r\n\r\nThe deletes are soft so it is possible to un-delete by sending an Undo activity. PieFed keeps soft-deleted posts (topics, in NodeBB language) for a few days then after a week deletes the content from the database. \r\n\r\nAll of these activities are enclosed in an `Announce` and the http POST is signed using the community key. So in a way the content 'belongs' to the community, not to the original author. With that model of ownership the idea of removal redundant - a post without a community is not a post. \r\n\r\nTangentially - it would be good to come up with a way to move a topic to another category and federate that so the move can happen on other instances, too. We could go off-piste and create a `Move` activity, or use `Remove` (from old topic/comm) followed by `Add` (to new topic/comm) to do the same thing. I feel more inclined to go with `Move` as it's a single atomic operation that either succeeds or fails, despite it not being in the spec. \r\n\r\nThe AP spec is so badly stretched by various implementation-specific differences that I don't think it's worth being ideological about adherence to it it anymore. ",
"sig": "a596dfba0020ec7ff5bd5d2c0ee5c685a06281aa6b67a47c5e0358df33949c9d7a69572b7a975d3a0ec40ddc04de436e85267a88ada4fc1f4e253cde44e35000"
}