All devices on the Web are recognized by a unique number called an IP address, such as 184.108.40.206. When you have a site, the domain name that you type to access it is to save you time, but the server where your site files are still has an IP address. Considering that there're many more websites and devices than there're IPs, all shared web hosting servers have a number of sites under the very same IP, while using a dedicated server you'll be given a dedicated IP too. Even in the first case though, you'll be able to obtain a dedicated IP for your sites and host them on a shared server. One benefit would be that you will have superior search engine rankings because a dedicated IP usually means a faster loading website. What is more, you need such an IP when you intend to acquire an SSL certificate for your website and shield the info that visitors submit on it.