According to
this Wirelessweek article, screen size is the key factor to a successful smartphone. Smartphone sales are ramping up; their sales have grown by 50% over the last year, distributing over 72.9 million units. Gartner even estimates that 450 million smartphones will be shipped internationally by 2010. This is a huge number, and a great indicator of the power of the Mobile Web.

A
study by Berg Insight predicts that 113 million smartphones will be sold this year, reaching 365 million units in 2012.
According to Thomas Thornton, a senior research scientist at Perceptive Sciences in Austin, Texas, screen size matters. As the screen size increases, the displayed content also increases. Thus, popular websites like
MySpace and
YouTube can be accessed with higher quality displays. With the screen resolution available on some smartphones, specifically
the iPhone, loads of multimedia options are readily available.
Also, with the developing high speed wireless broadband networks emerging, the experience on a smartphone will further resemble the experience through a wired connection. As more and more smartphones are sold, the Mobile Web will inevitably develop. If the goal is for the "Mobile Web" and "Web" to converge and have the experience be consistent, then larger displays on smartphones will be necessary. With the hardware keyboard taking up valuable real estate on the phone's body, the most logical solution is to implement a software solution, much like the iPhone. Another solution, as seen on
AT&T's 8525, can be a sliding keyboard, but this just creates a brick of a phone - and there's nothing hip about a square smartphone.