Hello friends.whatsapp is the best social network till now.best feaature of this app is the security.no unknown member can enter and read your profile and know about you.only those friend can know and see you those phone number is saved in your mobile only if you wan to add his/her.we can chat, send voice sms, video sms very easily without cost.
You can share anything.a video file can upload and download very easily.now whatsapp has mad free use of this app, earlier there was annual subscription bu now it is free.my recommendation is we must use this app.there is no harm but not addict of this app.