All devices on the Web are identified by a specific number called an IP address, such as 188.8.131.52. In case you have a website, the domain that you enter to be able to access it is to save you time, however the server where your site files are still has an IP address. Due to the fact that there are a lot more websites and devices than there're IPs, all the shared website hosting servers have a number of sites under the very same IP, whereas using a dedicated server you'll have a dedicated IP as well. Even in the first case though, you'll be able to get a dedicated IP for your websites and host them on a shared server. An advantage would be that you'll get superior search engine rankings as a dedicated IP usually means a faster loading site. What's more, you need such an IP in case you would like to acquire an SSL certificate for your website and protect the information that your visitors submit on it.