Tango is downloaded over 200 M+ times and it has over 160 M+ active users which is really a great user base. You can use Tango as your main social media app to chat with your friends and do video calls for free.
Similar as Whatsapp, Viber and Line, you also don't need to create a profile and log in everytime you want to use Tango. You only need to verify your mobile number once. After you have verified your mobile number, Tango automatically finds your friends who are also on Tango. You can choose any from list of online users to start communicating with them. Same features are also available in Tango for PC.