An IP address is a unique number which separates a site or a hosting server on the world-wide web, so if you have a dedicated IP, it will be employed exclusively by your sites and will not be shared with other individuals as it happens with shared hosting accounts. Provided you have your own web server, you will have a dedicated IP, but you may require additional ones for various purposes. If you have a web-based store, for example, you shall need an SSL certificate for it, in order to ensure that the payment information which your customers submit will be encrypted and safe. 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 machine. You might also need an individual IP for an app such as a VoIP server, or if you need a slightly better overall performance for a given Internet site, which will affect its position in search engine results.