How well does your website display on a small screen? Have you checked? Can all your website visitors, regardless of whether they are on a desktop, laptop, tablet or mobile phone, all get the same content and ease of use?
If they can’t then you’re letting them down and potentially harming your business growth. If your website isn’t responsive then people will not sit there doing the pinch and zoom routine just because your website is obsolete.
Responsive design means one website for all website visitors
You do not need different versions of your website. Responsive design simply means that the website will automatically fit on all screen sizes and even change font sizes, header layout, menu positions which images to load (etc) depending on screen size.
The number of people who use the internet from their mobile phone and nothing else is growing rapidly. Facebook and Twitter are constantly reporting that the mobile phone is taking over and any website analytics will report the same trend.