An IP (Internet Protocol) address is that every server with access to the internet has to be able to be located by other servers. This is a unique address; albeit, it can be shared by several users, kind of like several inhabitants of the same house having the same postal address. And then there is the dedicated IP address, which is for the sole, exclusive use of just one owner.
Now, if you are the type who just hates sharing - a shared IP address is not for you. You would require a
dedicated IP address for your own, personal use. A superb benefit of this is that your site remains completely unaffected by another site that exists on the same server but with a different IP address. Even if the site is a spammer and is blacklisted, your site remains untouched by its malignancy.
If your site is for transactions and you require an
SSL certificate, you would most definitely require a dedicated IP address since every e-commerce site would need one. This would ensure secure connections and peace of mind too!