Should You Interlink Domains?
It’s not uncommon for one business to have a number of different entities operating in completely different markets. There are hundreds of global corporations, each of which has dozens of subsidiaries working within the same organisation. However, even smaller businesses can have offshoots.
If each of these brands has a website, you might think that it is only natural to interlink it to others in the same group. In many ways you’d be right too. However, if you create a network of sites, each of which are passing links to and one another, this could potentially catch the eye of Google. So you do need to tread carefully.
Providing links for the sole purpose of passing domain strength is against Google’s webmaster guidelines. PageRank manipulation does go on. Plenty of companies, small and large, have deliberately sought to improve the collective visibility of all domains within the business by creating ‘false’ networks or exploiting the strength of one to benefit another site. But not everybody is deliberately interlinking
Don’t link from every page
If you want to join your domains but avoid tripping some kind of penalty, then avoid excessive linking. For instance, if you have decided to include a link to an otherwise irrelevant site in your footer, then you could potentially create thousands of outbound links. If the target site does exactly the same, suddenly it’s a reciprocal link and unlikely to do much good to anyone.
What’s the solution?
If you have decided that you desperately want to have links plastered on each page, then make sure that they are no-followed. This will show Google that you acknowledge the sites are related but that you don’t want to pass on link strength. As a result you shouldn’t experience any adverse affect and customers can still hop between your domains if they should so wish.
This becomes all the more important if you have decided to host all the websites on one IP address. Again, the search engines will understand that businesses can have multiple subsidiaries, each of which require their own website, so won’t punish you for setting these up. However, if you start doing link building between all of them, with followed links and no sign of trying to suppress any kind of PageRank manipulation, then your rankings might suffer.
You can get away with it though and I’m sure many people do, but it isn’t best practice and any kind of search engine algorithm update could quickly eradicate any benefits that you may have enjoyed. So be careful with your domains. Keep them separate and only provide links where necessary – considering no-follows everywhere else.