Android users who used Whatsapp have no intention of paying the annual fee to use this famous instant messaging service. Therefore, Line has exceeded Whatsapp for the first time in Android devices, now Line is among the most downloaded free applications on Google Play.
There are other free apps for android providing instant messaging service, like Viber, Voxer and Tango, but no so popular as Line.
It is worth remembering that even Whatsapp can be downloaded for free, but it charges since the first year of use. Moreover, Android app Line has no cost, because the money they get is from the sale of emoticons and drawings purchased by users who want to have a customized program.
As Viber and Tango, Line also has the ability to make free calls between users who have installed the app.
All these Free calls & Message applications can be downloaded from Google Play.