All devices on the World Wide Web are identified by a unique number called an IP address, such as 123.123.123.123. If you have a site, the domain that you type to access it is for your convenience, however the server where the website files are still has an IP. Because there're far more sites and devices than there are IPs, all shared website hosting servers have a number of sites under an identical IP, while with a dedicated server you will have a dedicated IP too. Even in the first case though, you're able to acquire a dedicated IP for your sites and host them on a shared server. One benefit would be that you will have better search engine rankings since a dedicated IP generally means a faster loading site. What is more, you need such an IP when you would like to purchase an SSL certificate for your site and shield the information that visitors submit on it.