Designing for mobile has evolved dramatically. Users now expect fast, immersive mobile experiences, and catering to this is increasingly difficult.
It was clear mobile use was going to take over; designing for mobile pushed you to better and simpler designs because of constraints like small screens and slow networks; and last but not least, mobile devices had capabilities like multi-touch and location detection that allowed you to create new kinds of experiences.
Read more: @ http://mashable.com/2013/06/02/mobile-design-tips/