All devices on the Web are recognized by a unique number called an IP address, such as 126.96.36.199. In case you have a website, the domain name that you enter in order to load it is for your convenience, yet the server where your site files are still has an IP address. Due to the fact that there are many more websites and devices than there are IP addresses, all of the shared web hosting servers have a number of websites under an identical IP, while using a dedicated server you will have a dedicated IP too. Even in the first case though, you can get a dedicated IP for your websites and host them on a shared server. An advantage would be that you'll enjoy better search engine positions since a dedicated IP often means a quicker loading website. Furthermore, you need such an IP when you plan to acquire an SSL certificate for your site and shield the data that your visitors submit on it.