When people want to buy a domain and set up a blog on that URL, they will have to host the site somewhere.

You can choose to have either a static or shared IP address with your hosting provider. When I started my site, I was told that you need to have your own individual and static IP address if you want to rank high for key terms especially if you are in a competitive industry, however there is no conclusive evidence to prove this. People also talk about Shared IP Vs Dedicated IP but what exactly is this?

Shared IP
This is what you get by default from your hosting provider. It means there are many domains on the one IP eg 192.80.30.130. When a browser requests a page from that site inside that IP, the server will check the domain being requested and then serve that page.

Dedicated IP
When you buy your hosting solution, you can request to have a dedicated IP, which means your site will have a unique IP, not shared by any other sites.

So what are the disadavantages?

If you have a shared IP and if one of the sites sharing the IP gets a penalty for spam, link farming or adult content, then your website will also suffer the consequences. However this is rare and should be taken into consideration when purchasing your hosting package.
If you want a dedicated IP address, it costs more, not by much over the year, about thirty pounds, dependant on the package.

There is not one answer that says having a static rather than a shared IP address is any better. It does cost you more though to have your own static IP address. If you are going to have a big site and require a lot of storage, it is recommended to have a static IP address.