(Inc.) — Several companies have a subdomain set up specifically for mobile phones. So, for example, when users type http://www.ESPN.com into a smartphone, the ESPN site actually figures out that they are visiting the site from a mobile device and redirects them to a subdomain. The user experience from the phone is different than the user experience at a computer. Diane Irvine, CEO of Seattle-based jewelry site Blue Nile, realized the importance of mobile delivery when her site made a $40,000 diamond sale via a mobile device in 2009. She soon learned that she needed to make her site more mobile-friendly for iPhone users. Last year, she introduced a mobile version of the Blue Nile site. Since the launch, Irvine says, “More than 20 percent of our shoppers are using the mobile site.” The reason being is that it gives people the flexibility to shop wherever they are. “This will become the future of shopping,” she adds.