All devices on the World Wide Web are recognized by a unique number called an IP address, for example 123.123.123.123. If you have a site, the domain name that you enter 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 many more sites and devices than there are IPs, all the shared web hosting servers have a number of websites under an identical IP, whereas with 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 sites and host them on a shared server. One advantage would be that you will get far better search engine positions as a dedicated IP generally means a faster loading website. In addition, you need such an IP when you would like to purchase an SSL certificate for your website and shield the data that your visitors submit on it.