All devices on the Internet are recognized by a unique number called an IP address, for example 126.96.36.199. When you have a site, the domain name that you type to access it is to save you time, however the server where the website files are still has an IP. As there're many more sites and devices than there're IP addresses, all shared web hosting servers have a number of sites under the same IP, whereas using a dedicated server you'll get a dedicated IP too. Even in the first case though, you will be able to get a dedicated IP for your websites and host them on a shared server. One benefit would be that you may have superior search engine rankings as a dedicated IP usually means a quicker loading website. Also, you need such an IP in case you intend to acquire an SSL certificate for your site and secure the information that your visitors submit on it.