I’m sorry to say that that other Warrior you’ve paid attention to in the past is wrong or you may have misunderstood what he meant.
Google’s algorithm doesn’t treat links differently based on IPs nor domain names, and why should they? Does having links from different IPs or domain owners make your page better results for their searchers. What does this have to do with relevance?
Google is trying to deliver results that satisfy the searcher’s needs. If you link to other pages where it makes sense to do so you will be improving both the page where the link is placed and the page it links to.
Google does attempt to fight spamdexing, which involves a number of techniques that involve artificially manipulating PR or placing unwanted advertising messages in inappropriate places. So if you are interlinking simply for the purpose of spamming your own websites, then you are as likely to have those pages devalued on different IPs as you would having them on the same IP. Google isn’t so easily fooled by such tricks.
Do you really think they are going to look at spam that originates from different IPs, domains or website owners as okay while spam on the same IPs, domains or website owners are not? Do you think Google’s users like spammy sites better as long as those sites are spammed by different owners or different IPs?
Folks are just buying into a myth created by hosting companies that want to sell you on their premium-priced hosting plans. There may be valid reasons to use unique IPs and they typically involve hiding your identity or affiliation with other websites, but there is no SEO advantage.
