It is a situation many of us have been in. You send an important message on WhatsApp and then eagerly wait for a reply.
One little tick appears to your message. Then two. Then nothing. Your heart sinks.
The important message has been ignored - or has it?
Up until now many users incorrectly thought the double check indicated a message had been seen.
Actually it meant that a message had been received by the handset, not its human owner.
However, WhatsApp's official website has confirmed the messaging service has a new feature, so you'll know when someone has definitely read your message.
We introduce to you, the double blue tick!
If a group of people are chatting, the two blue ticks will appear when everyone in the group has read the message.
Two grey check marks will show up when everyone has received the message.
You can also find out the time a message was delivered and read by pressing the message with the double tick - then holding it for a couple of seconds, before selecting "info".
Other messaging services already have similar types of notifications to show when someone has seen a message, like Facebook.
In 2013, instant messaging apps like Apple's iMessenger, WeChat and Viber overtook the traditional SMS text message for the first time.
Research company Informer found almost 19 billion messages were sent on chat apps in 2012, compared to 17.6 million texts.
Newsbeat has contacted WhatsApp for an official response. But we're still waiting for the double blue tick...