Nowsadays, having a mobile version website is becoming increasingly important. Smartphones and tablets can access any website on the web; however, that does not mean the experience will be a pleasant one. If your website is not built or optimized for mobile devices, your users will be dealing with a longer load time (if it loads at all) and a lot of zooming and pinching to read the text. If that doesn’t convince you, here are 8 more reasons to go mobile.
Source : Our Mobile Planet - http://services.google.com/fh/files/blogs/our_mobile_planet_us_en.pdf