All devices on the Internet are recognized by a special number called an IP address, for example 184.108.40.206. When you have a website, the domain name that you enter to open it is to save you time, but the server where your website files are still has an IP address. Due to the fact that there are a lot more websites and devices than there're IPs, all of the shared hosting servers have a number of websites under an identical IP, whereas using a dedicated server you'll have a dedicated IP as well. Even in the first case though, you are able to acquire a dedicated IP for your websites and host them on a shared server. One advantage would be that you may get better search engine rankings because a dedicated IP often means a faster loading site. What is more, you need such an IP if you want to get an SSL certificate for your site and secure the info that your visitors submit on it.