[masalah]

Concerning sms in many of the countries worldwide sms is not free/unlimited as the case in the us you only get a specific amount in your plan with extremely late/unreliable delivery so it's basically unusable for chat where I'm from and only works in the case of ads and credit card transaction notifications.

whatsapp also had the advantage of being simple to use requiring only your phone number and it worked on pretty much any phone you had from symbian feature phones to the latest iphone helping it to gain widespread traction among people.