
Soon after, Jan also joined Yahoo, as a Security and Operations Engineer. The two liked each other and became friends.

Jan and Brian met in 1997, while Brian was working as a software engineer at Yahoo. With WhatsApp however, there are a series of events that led founders Jan Koum and Brian Acton to build the world’s most used messaging app. And most times, it’s the right man at the right time. When we look into the history of how an app or company was developed, there is always an interesting story. And this brings us to the topic of the day – how was WhatsApp developed and how did it become the top most used messaging app today? In comparison, Facebook’s Messenger takes second place with only 1.3 billion. However, by far the most popular instant messaging app today is WhatsApp with 2 billion monthly users.

As for socializing, we literally have thousands of apps to choose from. In our work, we use emails and platforms like Slack or Microsoft Teams. Today, instant messaging is an important part of our lives. So much so, that by 1965, hundreds of MIT and New England University students were already registered users. Not surprisingly, this new system was an absolute success. This system resembled today’s email services and allowed up to 30 users to log in simultaneously and message each other. The idea of instant messaging first started in 1961 when the Computing Center at MIT – Massachusetts Institute of Technology – created the Compatible Time-Sharing System (CTSS).
