An IP address is a unique number which identifies an Internet site or a hosting server on the world-wide web, so in the event that you have a dedicated IP, it shall be employed only by your Internet sites and won't be shared with other people as it happens with shared web hosting accounts. Provided you have your own web server, you'll have a dedicated IP, but you may need additional ones for a variety of uses. Provided you have an electronic store, for example, you will need an SSL certificate for it, so as to make sure that the payment information your customers submit shall be encrypted and protected. The same is valid if you have a login form of some type and you would like the usernames and the passwords that visitors enter to be protected. The SSL certificate requires a dedicated IP, which has to be different from the one which you already have on the hosting server. You could also need an individual IP for an app such as a VoIP server, or if you want a slightly better performance for a particular website, which may influence its position in search engine results.