@mczachurski@mastodon.social @wakest@public.mitra.social It doesn't need to scale because mitra servers are small. Also, ActivityPub requires delivery to personal inbox if shared inbox is not available: Origin servers sending publicly addressed activities to sharedInbox endpoints MUST still deliver to actors and collections otherwise addressed (through to, bto, cc, bcc, and audience) which do not have a sharedInbox and would not otherwise receive the activity through the sharedInbox mechanism. -- https://www.w3.org/TR/activitypub/#shared-inbox-delivery