04 April 2021 - 00:02 By Sandiso Ngubane Barely a year since its launch, the audio-chat app Clubhouse is earning love and criticism and courting competition in equal measure. The app recently announced it had reached 10-million active users. But security concerns have plagued its meteoric rise as signing up requires a phone number, and once you're signed up, any other user who has your contact in their phone book has access to you. In China and the United Arab Emirates, governments have moved quickly to block the app in what are seen by many as attempts to curtail free expression... This article is reserved for Sunday Times subscribers.