Many companies own many different websites. For example a publishing company may own 20 different sites for its 20 magazines. Now what's to stop them putting a link to each site in the footer of each site?
What's the effect on SEO of doing this?
I’ve looked into this linking issue and there are hundreds of conflicting views about the effects of it. I can’t find anything that says it’s either bad or good.
This forum covers both interlinking sides of the argument and leads me to the following conclusions:
- Google will treat links between sites from the same server like internal links – some weight, not much.
- From a usability perspective it would NOT make sense to include links to your unrelated sites in the footer.
- From a usability perspective it WOULD make sense to include links to your related sites in the footer.
- Spamdexing (linking lots of sites purely for SEO) is punished.
- If you design for the user you won’t be punished.
If a publishing company has a site for accountants it would make no sense whatsoever from the user's point of view to link in the footer to their site aimed at 10 year olds.
However if they were to link to a site for human resource professionals in the footer of the accountancy site it may make more sense.
If you think about this subject from Google's point of view why would they want to punish someone who's genuinely trying to give the user a good web experience and also encourage visits between related sites?
Link your relevant sites together, it will help your SEO as much as internal linking will (ignore internal linking at your peril), however don't do anything EVER that will not benefit your users, confuse them or send them to places they don't want to go.