All devices on the World Wide Web are identified by a special number called an IP address, for example 188.8.131.52. If you have a site, the domain that you enter to be able to access it is for your convenience, however the server where the site files are still has an IP address. As there're far more websites and devices than there are IPs, all of the shared hosting servers have a number of websites under an identical IP, whereas when you use a dedicated server you'll have a dedicated IP too. Even in the first case though, you'll be able to get a dedicated IP for your sites and host them on a shared server. One benefit would be that you will have superior search engine positions since a dedicated IP often means a faster loading website. Also, you need such an IP if you plan to get an SSL certificate for your site and shield the information that your visitors submit on it.