More and more people are using smartphones, tablets and other other devices to use the Internet, so it is important to create a website that is easy-to-read in a variety of different screen sizes (using a mouse or a touchscreen).  By easy-to-read we don't mean a very tiny version of your page, we mean a page that re-formats itself so that the important information is right there front and centre all the time.  The technical term for this is 'responsive design' and we do it.