All devices on the Internet are identified by a special number called an IP address, such as 220.127.116.11. If you have a website, the domain that you type to load it is to save you time, but the server where your website files are still has an IP. As there are many more websites and devices than there're IP addresses, all shared hosting servers have a number of websites under the same IP, whereas with a dedicated server you'll be given 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 get improved search engine positions because a dedicated IP generally means a quicker loading website. What's more, you need such an IP in case you intend to obtain an SSL certificate for your website and shield the data that your visitors submit on it.