All devices on the World Wide Web are recognized by a special number called an IP address, for instance 123.123.123.123. If you have a website, the domain that you type to load it is for your convenience, however the server where the website files are still has an IP address. Due to the fact that there are far more websites and devices than there are IPs, all of the shared hosting servers have a number of sites under an identical IP, while with a dedicated server you'll be given a dedicated IP too. Even in the first case though, you can get a dedicated IP for your websites and host them on a shared server. One benefit would be that you may get better search engine rankings because a dedicated IP generally means a quicker loading website. What is more, you need such an IP in case you would like to obtain an SSL certificate for your site and protect the data that visitors submit on it.