All devices on the World Wide Web are recognized by a specific number called an IP address, for instance 18.104.22.168. In case you have a site, the domain name that you enter in order to load it is for your convenience, however the server where the website files are still has an IP address. As there're far more sites and devices than there are IPs, all shared hosting servers have a number of sites under an identical IP, whereas with a dedicated server you'll get a dedicated IP too. Even in the first case though, you are able to get 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 as a dedicated IP generally means a faster loading site. In addition, you need such an IP when you want to purchase an SSL certificate for your website and shield the data that visitors submit on it.