This was also the first time we had a decent useable internet web browser on a phone, allowing people to browse the web whilst out of the office. This has led to an increase in special websites that have been 'optimised' for use on the smartphone sized screen.
There are some problems with creating a mobile version of your website.
Typically the most prevalent problem is that the content you have on your website is just not suitable for viewing on a smartphone.
The easiest way around this problem is to create a separate mobile website with a corresponding mobile page for each page on your website. The reason for an exact duplicate from a page point of view is that Google crawls the web with mobile crawlers as well as normal crawlers and it will find missing links if it does not find the pages it expects to see.
Mobile users will also have trouble if the website auto-detects they are using a mobile, as they may wish to view the normal website and will be unable to do so.