> imagine an 'OK' button on a text message that lets the sender know you've seen it, without the need to send a message saying just that yourself.
That already exists in the form of "read notifications".
That's why I really like them. If I go away for 5 minutes in the middle of conversation, I don't have to tell the person about it, they'll see their messages were no longer read.
I never found those to be an adequate solution. It's fine for an ongoing conversation, but for a singular message it's useless. I might get it and see it, but not read it yet. Just because I'm at my computer or phone doesn't mean I'm reading and acknowledging the message.
That already exists in the form of "read notifications".
That's why I really like them. If I go away for 5 minutes in the middle of conversation, I don't have to tell the person about it, they'll see their messages were no longer read.