How best to link multiple related websites.

[EugeneF]

I have a handful of e-commerce websites that overlap each other some in the same niche.   I have already heard that it would have been best to make just one website, but this is not practical for me.  Our business model goes back to a time before the internet.  We have relationships with manufacturers where they refer business to us because we brand web sites which will not switch customers to competing brands.  Our agreements make it ok to link to other websites so long as we have branded websites that focus on the specific manufacturers.

For SEO, what is the best way to link these sites?

Site wide links in footers.?

Single links at on homepages?

One way links from the most powerful site?

Some other method?

We have been wrestling with this question for some time.

[RobertFisher]

Eugene

We link a lot of sites very similar sites within the same vertical. Like you, "we have our reasons" as opposed to having all on a central site with either sub directories or sub domains. What we have found is this:

First, you link from content to content. You do not link from footers or sidebars site wide. So, if you have a page on wrenches and you are linking to a site that sells the same type, I would link from a good description on Site A to a paragraph or page on that wrench on site B. (Obviously, if you have several places you can link from regarding the wrenches link from each to pages you believe will best be served by the links based on the business objectives you wish to achieve.) - Note: I am assuming you know about anchor text, etc.

Second, it sounds as if you have more than two sites. Given that I would use some type of matrix that prevents me from creating reciprocal links. So, Site A links to Site B. (B does not link to A). Site B to Site C (no C to B) and, then, you can link from C to A. With more sites, there are more variations. I am quite visual so I first draw diagrams out and then when I have reviewed it thoroughly, someone else on the team vets it and only then are the links placed.

Third, typically those with multiple sites have them all on the same server and this is not helpful. Where you can, I suggest moving the hosting so that you have a good variation of IP addresses and you do not duplicate C blocks. You need to just be able to keep up with various hosts.

Lastly, I really work to get other high quality links - .edu, professional organizations, etc. Again, using wrenches, if you sell to ASE certified mechanics you might want to try that. (Not an area I handle so treat it as a widget example). If all your links are coming from one site to another, sooner or later it has to have, minimally, a less positive effect. So having other good links is important.

Best of luck.

[RyanKent]

Robert's response is great. I will just add it is probably not worthwhile to attempt to vary your hosting to change your C block. The IP address is just one method Google can use to determine a relationship between sites. They can look at who registered the domain, the site code, similar backlink profiles and many other metrics.

[EugeneF]

Thanks, This helps a lot.   We are setting up linking so that we have no reciprocal links exist. (in fact we use something more like a>b>c>d>a). As I inspected domains, to my surprise, non are on the same C-Bock.   We are removing errant links and checking duplicate content.   Much of our content on the product item level is duplicate.  In the past, we simply published product text to the most relevant website a week before it hit the other sites.  Linking has been pretty organic, so link profiles are fine.  Some of the sites have results that show up close to each other in google SERP's now.

[EugeneF]

I figure they can find related sites in several ways.  How can you tell if they have made this determination?