What above all has to do with Responsive Website ??? Technology advancement not only changed consumer behavior for shopping but also how they access the resources available online, with the devices they use.

e:g:

If you are a startup or already online, what would be your preference, which Os, which browser, what resolution would you target. Wouldn't it be better to have one site compatible for all.

What the Heck is Responsive Website

Respond to environment: It should be flexible, adaptive and responsive to the devices accessing it. It should give the same feel and experience to a mobile user as it gives to a desktop user.

Is your website responsive, if not think over it.