WhatsApp, the smartphone instant messaging applications is massive. It has over half a billion users and sends billions of messages every day.
The service makes use of ticks at the bottom of the message to reflect the status of the message.
While many will welcome this added confirmation that a message has been received and read, there will be some that will not.
You may have used the excuse that you did not receive a message or an email. Now that the service will inform the person who sent the message that it was opened and so can be assumed that it was read or ignored, that excuse becomes tricky.
For others the time you take to reply or read a message might also have implications. Errant husbands and new romances all have implications depending on when messages were read and replied to.