An IP address is a unique number that distinguishes a site or a hosting server on the world-wide web, so if you have a dedicated IP, it will be used just by your Internet sites and won't be shared with other people as it happens with shared Internet hosting accounts. Provided you have your own server, you shall have a dedicated IP, but you may require extra ones for a variety of purposes. In case you have an Internet store, for instance, you shall need an SSL certificate for it, so as to make certain that the payment info which your customers submit shall be encrypted and safe. The same is valid in the event that you have a login form of some type and you would like the usernames and the passwords which visitors input to be secured. The SSL certificate requires a dedicated IP address, which has to be different from the one which you already have on the hosting server. You might also need an individual IP for an application such as a VoIP server, or if you would like a slightly better functionality for a particular website, which shall influence its position in search engine results.