Chapter 1. The Essentials of Responsive Web Design
Only a few years ago, websites could be built at a fixed width, with the expectation that all end users would get a fairly consistent experience. This fixed width (typically 960px wide or thereabouts) wasn't too wide for laptop screens, and users with large resolution monitors merely had an abundance of margin either side.
But in 2007, Apple's iPhone ushered in the first truly usable phone browsing experience, and the way people access and interact with the Web changed forever.
In the Responsive Web Design with HTML5 and CSS3 - First Edition, Packt Publishing, it was noted that:
"in the 12 months from July 2010 to July 2011, global mobile browser use had risen from 2.86 to 7.02 percent."
In mid-2015, the same statistics system (gs.statcounter.com) reported that this figure had risen to 33.47%. By way of comparison, North America's mobile figure is at 25.86%.
By any metric, mobile device usage is rising ever...