The startup launched in 2009 as a messaging service founded by Jan Koum and Brian Acton was WhatsApp.
Koum and Acton had both worked at Yahoo before creating WhatsApp. The service initially focused on status updates, allowing users to show whether they were available or busy. It then evolved into an internet-based messaging platform after users began using status changes to communicate.
WhatsApp became especially popular internationally because it supported messaging over mobile data and avoided traditional SMS charges. Its growth was accelerated by smartphone adoption and its simple address-book-based design. Facebook announced its acquisition of WhatsApp in 2014 for approximately $19 billion, one of the largest technology acquisitions at the time.
WhatsApp is sometimes confused with Telegram or Signal, which are separate messaging services founded later. WhatsApp also expanded beyond text messages to voice calls, video calls, group chats, file sharing, and business tools.