Apple's native iMessage and FaceTime were picking up traction on iOS devices. In 2014, Facebook bought WhatsApp, a mobile messaging app, and months later, users gained the ability to place calls across borders. WhatsApp took off globally. So did Tencent's WeChat.
Skype, meanwhile, implemented multiple redesigns and faced criticism from devotees. In 2016, Microsoft introduced Teams as a distinct "chat-based workspace" for organizations with Office productivity software subscriptions that would compete with Slack, which was then an emerging startup.