All devices on the Internet are identified by a special number called an IP address, such as 123.123.123.123. In case you have a site, the domain name that you enter in order to access it is for your convenience, yet the server where the website files are still has an IP address. Due to the fact that there're far more sites and devices than there are IPs, all of the shared hosting servers have a number of sites under the very same IP, while using a dedicated server you'll have a dedicated IP as well. Even in the first case though, you're able to acquire a dedicated IP for your sites and host them on a shared server. An advantage would be that you will enjoy better search engine positions as a dedicated IP often means a quicker loading website. What is more, you need such an IP when you want to acquire an SSL certificate for your site and protect the info that visitors submit on it.