Many large web hosting services are now offering dedicated IP hosting. This is a new feature, and dedicated IP web host companies clearly see a market and a demand for this. But why would you want to use such a host?
You probably have your web sites hosted on a shared hosting system at the moment, as this is the most common setup. It allows a web host to put many sites on a single server. This server will have an IP address, and this address covers all the sites hosted there. In other words, in a shared hosting setup, your site is 'grouped' with the sites of many other customers under the same IP address. This is also known as name-based hosting.
Why might this be a problem? There were rumors some time ago that the search engines would take note of the IP address of spammers' sites, and ban that IP, or else downgrade the sites covered by that address. This is a process also known as blacklisting. It shows now that this is unfounded, and search engines are clever enough to take action against individual domain names, though the rumors still pop up from time to time when search engines change their rankings and webmasters lose their traffic, and they look around for reasons .
Again, you may not want your site or sites to be on the same IP address as gambling or pornography sites. Although the association is not interested to a person looking at your site, some webmasters believe they may be 'tainted' by what other web site owners have on the IP address they are sharing with them, even if they are not spamming sites.
Some search engine optimization professionals now also recommend that webmasters get their own IP address from a dedicated IP web host for other reasons. If you have more than one site, and they are all on the same hosting service, they will all be on the same IP address. There are now reverse search tools, which will show all the domains which appear on the same IP address. If you run multiple e-commerce sites, your competitors will be able to get a list of them all. You can see why this might be bad for your business – most webmasters want the full list of sites they own or run to remain confidential.
Another reason SEO professionals give as a benefit of unique IP addresses is that if you have a network of sites, you can link between them without any risk of the search engines seeing the linking as suspicious, as it might if all sites are on the same IP address. As with most SEO-motivated attempts to understand search engine algorithms, this may or may not be true.