yes, its very useful, its always for free as long as youre connected to the internet.

It is a good software to talk with people who are living in different country, since its free so I love using it.

I've installed it before, but unfortunately my friends didn't use it. So I uninstalled it after 2 days..haha. Well, actually it'll be really useful if your friends use it too and you have good internet connection. All you need is an internet connection then you can make free calls and send free text.

Yes I know Viber, it enables you to send free text and make a call just by using internet. hahhah I have uninstalled that application since I don't use it that much. In addition, I already have whatsapp and skype installed on my phone, and it's just enough for me.

Zalo is another choice for you. So start with viber and enjoy! Good luck :)