Noticed today that chat messages on Facebook are getting a little check mark when they are seen by the recipient. This has been a part of WhatsApp's client behaviour for a while now. I guess this is happening because a lot of users are accessing FB through their mobile phones.
Also there were issues with messages not being delivered during temporary connection outages. I suppose this was introduced to indicate the delivery of the message as well.
Any guesses on how be long before we start seeing two check marks for every message? :)
What if FB bought WhatsApp?