All devices on the Internet are identified by a specific number called an IP address, such as 220.127.116.11. When you have a site, the domain name that you type in order to load it is to save you time, yet the server where your website files are still has an IP address. Due to the fact that there're many more websites and devices than there're IPs, all shared website hosting servers have a number of sites under the same IP, whereas when you use a dedicated server you'll get a dedicated IP too. Even in the first case though, you can acquire a dedicated IP for your websites and host them on a shared server. An advantage would be that you will have far better search engine rankings since a dedicated IP often means a faster loading website. What's more, you need such an IP when you intend to get an SSL certificate for your website and secure the information that visitors submit on it.