I like Viber, but it is only good if the other person is on Viber. I have no problem getting my spouse to download an app to chat with me but most people don't. I couldn't get my own brother who simply said he had an unlimited SMS plan to avoid the hassle of this stuff. Two years ago I gifted Whatsapp to my entire extended family virtually no one downloaded it. While I have this stuff, I now just pop for Line2 which gives me unlimited SMS to the US & Canada and $.10 a minute elsewhere together with unlimited calls to the US and Canada. I have ATT's international data plan (unlimited worldwide data plan). I switch to 3g mode only when I live the US, slip on a Mophie case to deal with the added battery suck, and use this approach. Since I cancelled my SMS plan and lowered my minutes, I actually saved money.