If you host a website on a server, it employs the server's shared IP address - an exclusive number which is used to identify any device connected to the Internet. The domain name which you use for the website is for easy access and convenience of the website visitors, but on a more basic level, their Internet browser connects to the IP address of the server. Considering that there are a lot more websites than IPs, shared hosting servers use a single IP for multiple websites even in case they belong to separate users. Even though this doesn't affect your website performance directly, using a dedicated IP can slightly boost the loading speed of a particular site, providing it higher rankings in search engine results. Such an IP is essential for the installation of an SSL certificate too, so if you want to protect the payment or login data that your site visitors submit, you need an IP along with the SSL.