Is it worth it to spread a portfolio of websites accross numerous IP's? My dedicated server company offers IP addresses at about $5 a month (there may be a discount for multiple purchases) but basically I link to each of my websites; however, each link comes from the same single IP address I have. Do you believe it is worth it to pay for additional IP addresses simply so that you can spread the websites that you own and link to each other accross different IP's?
Google doesn't give more weight to separate IPs. It's based on the domain. Matt Cutts has said in the past that google will treat domains the same regardless of whether or not they are on the same IP. Making sure the links between your sites are relevant and useful is much more important than the IP address.
If the different ip theory would be true, I guess the best bet would be to have ip's on different c-block. But think of this, someone with a reseller account with 3 different ip's in same c-block wich can tell you they are on the same server, and that person as three different site about cats. He as found a keyword easy to rank for, let say "cat food". Now he optimise all 3 sites to rank for "cat food". Do you think google would let him dominate the serp for cat food. Surely they will check ip and domain details such as email of registrant to make sure their serp is not dominated by one individual. Google is not that stupid, dont you think ? The info is all over the net such as whois and even a basic ping reports the ip.
Anyone else care to chime in? I don't think they actively search like that unless it's a big time keyword where it looks like something fishy is going on.