Read Receipts on the GRAJ protocol. One fee. 195 countries. Join the protocol.
In commerce, whether a message was read is frequently a commercial fact rather than a social one. A price change, a delivery date or a term nobody acknowledged is the beginning of most disputes about what was agreed.
Delivered means it arrived. Read means somebody opened it. Acknowledged means they said they accept what it said — and only the third one settles anything, which is why the first two are a weak substitute for it.
Not surveillance of colleagues. Whether the counterparty saw the notice that the ship date moved, before the shipment moved, is the sort of question a dispute turns on and the sort nobody can answer afterwards.
A receipt tells the sender something about the recipient. Where it is on, both parties should know it is on — a one-sided signal is surveillance regardless of how useful it is.
Designed, not built. Messages are events in the append-only log today, which is where a read event would sit; the receipt itself does not exist.