There are 1 billion smartphone users in the world; according to a Morgan Stanley study this number of smartphone users is growing at a rate of 42% worldwide. The popularity of tablets is also increasing and, in 2014, the demand for these devices even surpassed the demand for laptops, with the sale of 175 million more units than the number of laptops. The numbers are from IDC.
Taking into account the constant technological evolution visible in the significant numbers present in the studies carried out, it is no longer possible to imagine a website with a resolution that is only adapted to a computer since this creates a poor experience for the user who surfs the Internet on mobile devices. The solution would, therefore, be to have different versions of the website for a smartphone and a tablet. However, these devices have numerous sizes and therefore numerous resolutions, making it impossible to create a different version of the website for each one. Furthermore, if there were several versions of the website, there could be a risk of errors and possible loss in terms of SEO. This is where Responsive Design comes in.
Responsive Web Design, as the name suggests, is the ability of a website to adapt to the different screen sizes.
This technique is achieved through the use of fluid layouts so that it can easily adapt to any screen size, fluid grids based on the content of the website and the use of @media queries which help to adapt to the different screen sizes that exist today. Thus, the user that visits the website on a smartphone, a tablet or on a PC, will see the website automatically adapt to the screen size of the different devices.
Google has confirmed that for SEO, responsive design is the most suitable since it easier for the search engine to realize that the website has a layout that adapts to any screen rather than to understand that there are various versions of the same website and not simply copied content.