All devices on the Web are recognized by a specific number called an IP address, for example 123.123.123.123. In case you have a site, the domain that you type to open it is for your convenience, yet the server where your site files are still has an IP address. As there are many more sites and devices than there are IP addresses, all shared hosting servers have a number of sites under the very same IP, while using a dedicated server you'll get a dedicated IP as well. Even in the first case though, you are able to acquire a dedicated IP for your websites and host them on a shared server. One advantage would be that you will have better search engine rankings since a dedicated IP usually means a faster loading website. What's more, you need such an IP when you intend to obtain an SSL certificate for your website and secure the info that visitors submit on it.