Jan Koum explains how listening to users helped him stumble on the idea for WhatsApp

When Apple introduced push notifications, we introduced a feature where if you change your status, it could go out to all the people and kind of broadcast your status update. And we've noticed that some people were actually using it as a communication method. And then people would also write in to us and say, look, you kind of have this way for me to communicate with my friends using push notification. Meanwhile, I'm paying €25 cents for a text message or whatever the crazy prices were at that time. Why don't you just pipe it together? You're like 90% there. You already know who in the address book uses WhatsApp. You're already using push notifications. And we kind of said, well, yeah, we got nothing to lose, so we'll try that. And so we did. And it turned out that that was actually the problem that had to be solved. Because SMS was really expensive, it was unreliable, it was 20 years old. It was very limited in what it can do. And this is always in one country. Imagine if you're trying to message across countries, across borders, and all of a sudden you have to pay like almost €1 for a message. It was ridiculous. And so all of a sudden we realized that we were solving a problem for people and then it just took off.