All devices on the Internet are recognized by a special number called an IP address, for instance 123.123.123.123. In case you have a website, the domain name that you type in order to load it is to save you time, however the server where the site files are still has an IP address. Due to the fact that there're a lot more websites and devices than there're IPs, all of the shared website hosting servers have a number of websites under the very same IP, while with a dedicated server you will have a dedicated IP as well. Even in the first case though, you will be able to obtain a dedicated IP for your sites and host them on a shared server. One benefit would be that you may get better search engine positions because a dedicated IP often means a faster loading site. In addition, you need such an IP in case you would like to purchase an SSL certificate for your website and protect the info that your visitors submit on it.