1. Introduction

Up until recently, a personal computer in the form of a tower pc, laptop or net book was the main type of device used to interact with the internet.

But now smart mobile devices are becoming just as important. For example, over 10 billion mobile devices are expected to be connected by 2020 compared to 1 billion desktop computers.

For example iPhone, Android based phones, Windows based phones, tablets, e-book readers are all capable of providing an easy to use way of exchanging information and keeping in touch with people over the internet.