An IP address is a unique number which distinguishes a website or a web server on the world-wide web, so in the event that you have a dedicated IP, it'll be employed just by your sites and won't be shared with others as it happens with shared web hosting accounts. In case you have your own web server, you will have a dedicated IP, but you may need additional ones for many different uses. If you have an electronic store, for instance, you shall 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 kind and you want the usernames and the passwords that visitors enter to be protected. The SSL certificate requires a dedicated IP address, which should be different from the one that you already have on the machine. You could also need an individual IP for an app such as a VoIP server, or if you would like a slightly better functionality for a given Internet site, which shall affect its position in search engine results.