Wondering a proper reply to this various questions: 1. Multiple websites hosted on a same/shared/virtual Ip Address ? a. Does SERPs rate internal linking among this websites negative if all of them has same content ? b. Does SERPs rate internal linking among this websites negative if all of them do not have same content ? 2. Multiple websites hosted on same Class C Networks ? a. Does SERPs rate internal linking among this websites negative if all of them has same content ? b. Does SERPs rate internal linking among this websites negative if all of them do not have same content ? I had a couple of more questions in mind... will post them again
The idea behind google pagerank is that a link to one site from another is a "vote" for it and makes it more relevant. Linking to your own websites is biased and google, in their patent, talks about ignoring or devaluing the importance of links from the same owner. The same IP makes it easy to figure it out. The same class "c" makes it easier. Google also has the ability to check registar ownership so in the future they may ignore or devalue links from websites with the same owner regardless of where it is hosted- but I've seen no evidence they are doing this currently. There is nothing wrong with using the same IP as long as you don't want to cross link the sites. "Same content" is going to get you a duplicate content penalty regardless of where it is hosted. You aren't going to get a penalty for linking to your own sites, google is just more likely to not give the link as much importance - or ignore it. I know from personal experience that they do ignore links on the same class "C" in some situations because I had a retail site and set up a wholesale site for one product that we retail (different IP) and after 8 months, a PR6 link passed no PR even though it is the only outgoing link on the page. I really don't want the wholesale site to rank at all - (for existing customers only) but it's an observation. If you want to cross link your sites for passing PR, hosting is so cheap that you are better off going with different class "C" IP's.
Yeah but if pagerank passes through internal pages as well, why does the ip make any difference? Since each page is considered its own entity, I am not seeing how discriminating based on IP makes a lot of sense.
Because passing PR on internal pages isn't a vote for your site i.e. if you have 1000 internal PR4 pages it doesn't increase your home page to a PR6 (or whatever) but 1000 PR4 links from external sites would. They are treated differently in the google algorithm. Discriminating based on IP makes a lot of sense because the whole idea of PR is a "vote" for another site. The chances of having links from non-associated sites on the same IP linking to your site are infinitesimal. Google either devalues, ignores or it creates a flag from these sites which triggers a check of the registar information to see if ownership is the same. Google devalues sitewide links so that's why it is much better to have 100 links from different sites rather than 100 links from a single site.
Don't confuse PR with SERP placement. I've never personally seen IP matter when it comes to passing PR. SERP performance is another matter entirely and multiple backlinks from same IP (whether same site or multiple sites) will carry less weight than the same number of links from different IPs. I can't remember ever doing a test specifically on different IP's vs. different class C's ... I think its' just one of those rumors that I personally figured better safe than sorry and so we always try to get different class c's going when we can.
The "rumor" was around long before it came out in the google patent. Most of the time its hard to know if a site is passing PR because you have other links to a site and can't be sure of which site(s) are passing PR. I had a unique situation where I have a site where I didn't want any links to, but needed to have a link from the retail site for wholesale customers. That is how I personally experienced a site on the same class "C" (same host, different IP) not passing any PR. The google patent talks about techniques such as devaluing links on the same IP and class "C" - but not everything in the google patent is currently be used. Just because I have personally experienced it, it doesn't mean google does it in every case - my point is that hosting is so cheap that if you are serious about running multiple websites, saving a couple of dollars a month shouldn't even be a consideration because even if it isn't being done 100% today, it could be tomorrow and a few extra dollars to get around a potential problem is worth it- at least to me. I use four different hosts even though I have a server that could easily handle all of my sites. The extra cost is a small fraction of 1% of the revenue the sites generate. I also keep backup copies of my sites on the different hosts so if there is a serious problem with one host, it is just a matter of changing the DNS and a few mysql passwords to get the site back up on another server. Also, by registering your domains under different business names, or by using a proxy registar, it makes it virtually impossible for anyone to be able to determine an ownership connection between different sites.