Fully Responsive Websites
Some statistics say that over 75% of your website viewers will be using their phones. Because of this, Google recommended that websites be “mobile-responsive” so that phone users can easily read and use the website. A full mobile responsive site is one that automatically accommodates small screens (mobile devices) by changing the layout and text size according to the screen size.
For instance, this site is mobile responsive. You can either look at this site on your smartphone, or you can simply re-scale your browser window to a smaller size to see the layout instantly change to accommodate the changes in screen size. This means that all your content is accessible on any device you use.