All devices on the World Wide Web are identified by a specific number called an IP address, such as 123.123.123.123. If you have a website, the domain that you enter to load it is to save you time, yet the server where your website files are still has an IP address. Since there are a lot more sites and devices than there are IPs, all of the shared web hosting servers have a number of websites under the very same IP, whereas when you use a dedicated server you will have a dedicated IP too. Even in the first case though, you can get a dedicated IP for your sites and host them on a shared server. One benefit would be that you will enjoy better search engine positions because a dedicated IP usually means a quicker loading site. Last but not least, you need such an IP when you would like to obtain an SSL certificate for your site and secure the info that your visitors submit on it.