An IP address is a unique number that identifies an Internet site or a web server on the Internet, so in the event that you have a dedicated IP, it'll be employed exclusively by your websites and won't be shared with other individuals as it happens with shared website hosting accounts. In case you have your own server, you'll have a dedicated IP, but you may need additional ones for various uses. In case you have an Internet store, for instance, you'll need an SSL certificate for it, to make sure that the payment info 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 would like the usernames and the passwords that visitors input to be secured. The SSL certificate requires a dedicated IP address, which should be different from the one which you already have on the hosting server. You may also need an individual IP for an app such as a VoIP server, or if you want a slightly better overall performance for a given site, which will affect its position in search engine results.