An IP address is a unique number which identifies an Internet site or a web server on the world-wide web, so in the event that you have a dedicated IP, it shall be used solely by your websites and will not be shared with other individuals as it happens with shared Internet hosting accounts. If you have your own hosting server, you shall have a dedicated IP, but you may require additional ones for many different uses. If you have a web-based store, for example, you will need an SSL certificate for it, in order to make sure that the payment information which your customers submit shall be encrypted and secure. The same is valid in the event that you have a login form of some sort and you wish the usernames and the passwords which visitors type in to be protected. The SSL certificate requires a dedicated IP address, which should be different from the one which you already have on the machine. You might also need a separate IP for an app such as a VoIP server, or if you would like a slightly better performance for a certain Internet site, which shall affect its position in search engine results.