All devices on the Internet are recognized by a specific number called an IP address, such as 188.8.131.52. If you have a website, the domain that you enter to open it is to save you time, but the server where the website files are still has an IP. Since there're far more sites and devices than there're IP addresses, all of the shared hosting servers have a number of websites under the same IP, whereas using a dedicated server you'll get a dedicated IP as well. Even in the first case though, you will be able to acquire a dedicated IP for your websites and host them on a shared server. One benefit would be that you may get better search engine positions as a dedicated IP usually means a quicker loading website. In addition, you need such an IP if you would like to purchase an SSL certificate for your website and secure the data that your visitors submit on it.