An IP address is a unique number that separates an Internet site or a web server on the world-wide web, so if you have a dedicated IP, it shall be used only by your websites and shall not be shared with others as it happens with shared hosting accounts. In case you have your own server, you will have a dedicated IP, but you may require additional ones for different purposes. In case you have a web-based store, for example, you will need an SSL certificate for it, in order to ensure that the payment info which your customers submit will be encrypted and protected. The same is valid if you have a login form of some type and you wish the usernames and the passwords which visitors enter to be secured. The SSL certificate requires a dedicated IP address, which needs to be different from the one which you already have on the web server. You could also need an individual IP for an application such as a VoIP server, or if you would like a slightly better performance for a given site, which may influence its position in search engine results.