Some web hosting customers, especially those with dubious business plans who have hired SEO witch doctors, request that every web site be placed on a separate IP address. The theory is that Google is likely to discount the links between sites on the same IP address because such sites may be trying to artificially increase their PageRank. It would be silly for Google to do this since there could be hundreds or thousands of unrelated sites that share an IP address, simply because they are customers of the same web hosting company. Nonetheless, this seems to be a widely-held belief.
This is frustrating to those in the hosting business because IP(v4) addresses are a finite resource, and here in North America, requests for new IP addresses for IP-based web hosting must include a technical justification.
Today, Sean emailed Google to ask for clarification. I hope that Google will publicly state that using multiple IP addresses cannot be used to inflate PageRank.
Update (Thu, 09 Dec 2004): Google responds by saying, go ask someone else to speculate.
Date: Thu, 09 Dec 2004 14:33:35 -0800 From: firstname.lastname@example.org Subject: Re: [#17061378] Regarding the need for a static IP Address Hi Sean, Thank you for writing to us. Please note that we don't comment on webmaster techniques or the details of our search technology beyond what appears on our site. We've dedicated an entire section of our site to answering the most common questions from those who maintain and/or promote websites. You'll find all of our publicly available information posted at http://www.google.com/webmasters/index.html Besides this section of our site, we've created a newsgroup discussion forum for passionate Google users. At http://groups.google.com in the http://groups.google.com/groups?q=google.public.support.general group, many webmasters and Google users share their questions and expertise. We recommend performing an advanced search on this group if you feel your question is particularly challenging and you've been unable to find an answer on our site. To do so, go to http://www.google.com/advanced_group_search?hl=en and enter your search terms in one of the 'Find messages' fields at the top of the page. Type 'google.public.support.general' in the 'Newsgroup' search field, and click 'Google Search.' If you don't find an answer to your question, you can always post your question to the group to see if other newsgroup users have helpful advice. Please be aware that this content isn't posted by Google, and we cannot verify its accuracy. Regards, The Google Team
The state is that great fiction by which everyone tries to live at the expense of everyone else. - Frederic Bastiat