Since people have been asking about Whatsapp’s latest update, here’s what changed: Whatsapp introduced the blue double check feature which means that the message has been read. So now one grey check means the message has been sent, two grey checks mean it’s been delivered and the two blue checks mean it’s been read.
So now you can’t pretend you didn’t read the message anymore lol!
Update: Here’s Stoli Lebanon’s funny take on this update.
Updated (11/05/2014): The latest version of WhatsApp (2.11.43) now officially incorporates this feature, although it may not work on all smartphone models. In other words, a grey check means the message has been sent, two grey checks that it’s been delivered to the recipient, and two blue checks that it’s been read.
Until now, the tick marks accompanying your WhatsApp messages indicated one of two things: one tick to show that the message had been sent to the recipient and two to show it had been correctly delivered, which did not imply it had been read. The myth that the double check=message read eventually became so widespread that the company had to clarify how the ticks actually work on their official Twitter account.