A reply that stays in its thread or post no longer counts on its channel, and a mention in one clears as soon as you read the thread or post. A deleted message, or a deleted post, takes its mentions with it from the channel’s @, the Inbox and the app icon. Copying a link to a reply in a forum or gallery post, a search result, a pin or a reminder opens the post at that reply.
A forum’s or gallery’s list updates as people edit, reply, react, close or delete, and a post with a new reply moves to the top under Recent activity. A forum’s New post treats a command as a command, never as words to publish. The post page, search results, Activity and the Inbox say when an answer came with an app, and the Inbox names people instead of their handles.
Privacy & safety has Apps from other people’s accounts in conversations with me, on unless you turn it off. Communities have a role permission, Use apps from their own account, and the audit log says who allowed or stopped such apps and which app answered where. Screens name the community itself rather than its space, and a reply line says Sticker, GIF, Picture or Voice message.