An IP address is a unique number that distinguishes a site or a web server on the Internet, so if you have a dedicated IP, it will be employed exclusively by your websites and won't be shared with other individuals as it happens with shared Internet hosting accounts. In case you have your own hosting server, you'll have a dedicated IP, but you may need additional ones for various uses. Provided you have an electronic store, for instance, you'll need an SSL certificate for it, to ensure that the payment info that your customers submit shall be encrypted and secure. The same is valid in the event that you have a login form of some kind and you wish the usernames and the passwords that visitors type in to be protected. The SSL certificate requires a dedicated IP address, which ought to be different from the one that you already have on the hosting server. You may also need a separate IP for an app such as a VoIP server, or if you desire a slightly better efficiency for a given website, which may influence its position in search engine results.