Since Apple has decided to keep Apple Messages (iMessage) locked up to its platform, users the world over have chosen Whatsapp as the most common cross platform instant messaging platform. It allows you to send files and pictures. IT allows you to make Voice Over IP calls and is just an overall well designed easy to use tool.
Whatsapp requires a data connection (3G/LTE) to work. This means using Whatsapp while travelling requires you to buy a local SIM Card (when you travel) or buy an expensive data pack from your home carrier. Until now.
I first wrote about KnowRoaming in 2013 and explained how it can save money when travelling by switching you to a cheaper local plan travelling simply by using the company's intelligent SIM sticker.
Today KnowRoaming announced that their customers will be able to use WhatsApp for free when travelling. You don't even need to buy a data plan and no data charges are levied. As long as you have an active account with some money in it and switch to their service when you travel (which is automatic when you travel), you get free Whatsapp in any country they work in (100+ countries).
This offer is available to on any of their services (Global SIM Card, Global SIM Sticker and Global Hotspot). I use the Global Sticker Option, anytime I land in a new country, their app detects it and switches me to their service.