When you send someone a message through WhatsApp, in the first leg of journey, the message travels from your mobile phone to the WhatsApp server. By the way, did you know that now WhatsApp can also be easily used on a desktop or laptop computer? When a single tick gets displayed in the bottom-right corner of the message chat bubble, it means that the message has reached the WhatsApp server. This tick icon is displayed as an indication for the sender that the message had successfully delivered by sender’s mobile network onto the WhatsApp server. More Interesting Stuff: Great one line status messages for WhatsApp. Arrival of your message on WhatsApp server is only half the journey. After getting the message, WhatsApp server sends it to the receiver’s mobile device. When message gets delivered to the receiver, the single tick icon turns into an overlapping double tick icon. Double tick indicates that your message has reach the receiver’s device —this however does not mean that the receiver has read it. Reading of a WhatsApp message is shown by blue tick marks. You may get a rough idea whether the receiver has read your message by seeing his “Last seen” timestamp. But remember, there is a way to hide the last seen timestamp. If the receiver has chosen to hide his “last seen”, you will not get information on when he was last online. As soon as you send the message to someone on WhatsApp —you may sometime see a clock icon in the bottom-right corner of chat bubble. This icon means that the message is still waiting to leave your mobile device. It means that the message has not yet begun its journey to WhatsApp server. Clock icon usually appears when the network connection is slow. It is an indication that the message is waiting in your phone and as soon as WhatsApp will get mobile Internet connectivity with enough bandwidth —the message will be sent over to server. Sometimes clock icon sticks on and refuse to go away. It simply suggests that something is wrong somewhere in the network path. You should check your internet connection, if the clock icon has been there for quite some time.By the way, this is good time to act if you realize that you have sent the message to a wrong person! If clock icon changes into single tick, then you will not be able to stop a WhatsApp message. As soon as the network will allow message to reach the server —clock icon will turn into single tick. Thereafter, single tick will change into double tick when the message will reach the receiver’s phone. If no icon appears in the bottom-right corner of the message bubble, the reasons is that your internet connection is not working. Check it out! This was the story of WhatsApp tick marks. But in case you were actually looking for the meanings of WhatsApp smiley and other symbols, I have written a separate article for that too. I hope this solves the mystery of single and double check marks as well as the clock icon in WhatsApp. Let me, please, know your comments on this!