*app, not “up”
When I send people texts, they might be Apple users or any other various phones and texting apps, are any of their texting apps such that it notifies them when a message has been seen or read?
I don’t get “seen” or “read” information on my end. Do they?
No, it’s a bad analogy. SMS is more like shooting a homing missile at someone, and then walking away. It’s probably going to find them, but if it doesn’t, you won’t know until you ask them about it.
Lol, even better.
Though shouting into a room isn’t too far off - it’s sent via plain text, so anyone could on the IP network can read it, if they wanted to (the cell part is moderately more secure, though susceptible to man-in-the-middle, such as Stingrays).