WhatsApp has approximately three billion monthly users, while Viber has over 200 million. In a recent poll, user preferences for messaging apps were as follows: WhatsApp (31%), Signal (40%), Viber (3%), Facebook Messenger (4%), Telegram (11%), and something else (11%). Signal has an estimated user base of 40 to 100 million monthly active users. Signal offers end-to-end encryption and minimal data collection, unlike WhatsApp and Viber, which track user interactions and device information. WhatsApp uses Signal's encryption protocol.