All devices on the World Wide Web are recognized by a specific number called an IP address, such as 126.96.36.199. When you have a website, the domain name that you enter to be able to open it is for your convenience, but the server where your site files are still has an IP. Because there're far more websites and devices than there are IP addresses, all shared website hosting servers have a number of websites under the very same IP, whereas using a dedicated server you'll get a dedicated IP as well. Even in the first case though, you can acquire a dedicated IP for your websites and host them on a shared server. One advantage would be that you may get superior search engine positions because a dedicated IP usually means a faster loading site. What's more, you need such an IP when you would like to get an SSL certificate for your website and shield the data that your visitors submit on it.