Most people think that they have to choose between a website and a mobile app but the art of responsive design means that you can have a website that works well on all web enabled devices regardless of the size.
Responsive design essentially means that a website is built for the smallest device first (i.e. a smart phone) and then the layout is changed and displayed differently if more screen space is available.
This enables a website to be perfectly optimised for each type of device depending on size but also can be dependent on the orientation of that device. This means that in most cases there’s no need to pinch/zoom compared to a traditional website.
The advantage of responsive design is that all devices are using the same HTML so only one piece of code needs to be maintained compared with developing native apps for iPhone, Android and Windows devices.