The presentation discusses the rapid growth of mobile usage, highlighting that there are over 1 billion smartphones in the US out of 4 billion mobile phones. It emphasizes the importance of designing websites that cater to mobile constraints such as smaller screens and difficult input, recommending the use of HTML5, CSS3, and responsive web design. Additionally, it compares websites designed for mobile usability with those not optimized for mobile, illustrating the benefits of mobile-friendly design.