All devices on the Web are recognized by a unique number called an IP address, for instance 220.127.116.11. When you have a website, the domain name that you enter to be able to open it is to save you time, but the server where the website files are still has an IP address. Due to the fact that there are a lot more websites and devices than there're IP addresses, all shared website hosting servers have a number of websites under the very same IP, while with a dedicated server you'll have a dedicated IP as well. Even in the first case though, you will be able to obtain a dedicated IP for your websites and host them on a shared server. One advantage would be that you may enjoy improved search engine rankings as a dedicated IP usually means a faster loading site. What is more, you need such an IP when you want to buy an SSL certificate for your site and protect the information that your visitors submit on it.