So you have seen this feature already or not. A Blue tick indicates that the other side has read your message or not. Not sure what was their motivation, but this is going to create some interesting circumstances for sure.
Whatsapp enables asynchronous communication and in asynchronous communication it is important that you can respond when you want to instead of real time. Now this indication of that other party has read changes the dynamics of this communication. It is almost as important as let us say if secret.ly made all the profiles public. This kills the essence of asynchronous communication. And since there are no options to control this at a user level, it makes this feature a privacy killer. How many of us love to use read receipts in email anyways.
 And then how about people who are color blind?
Hope Whatsapp guys will figure this out and evolve this feature correctly. What do you say guys?
I’m using this user script which adds a circle to read messages on WhatsApp Web: https://gist.github.com/qgustavor/3bb2a3d34f04584b57da It’s just CSS so can also be implemented with a user style too.