[wunki]

No! It's of no interest to the sender when somebody has read their message. When building our invitation application we also had a feature that showed when somebody opened your invitation. But we quickly noticed that it was annoying because when you knew the sender would be notified, you wouldn't open the invitation to read it if you weren't sure you had the time to respond. It's the same with WhatsApp, the "social" pressure to respond because the other person knows you have read the message.