All devices on the World Wide Web are identified by a unique number called an IP address, for example 126.96.36.199. In case you have a website, the domain that you type to be able to open it is to save you time, however the server where the website files are still has an IP address. Considering that there are a lot more websites and devices than there're IP addresses, all of the shared hosting servers have a number of sites under the very same IP, whereas using a dedicated server you'll be given a dedicated IP too. Even in the first case though, you'll be able to obtain a dedicated IP for your websites and host them on a shared server. One benefit would be that you may have better search engine positions as a dedicated IP often means a quicker loading website. Also, you need such an IP if you plan to purchase an SSL certificate for your site and shield the information that visitors submit on it.