In a Question and Answer segment during one of his hangouts, John Mueller was asked about external links during a site migration.
One SEO professional explained to John that they are relaunching a customer website and moving it from domain A to domain B, and they are reconfiguring redirects that point to domain A for domain B.
Their question at this point is: will page authority and page ranking be negatively affected if there are many backlinks to domain A? Will future backlinks, which point to domain A, also be affected?
Will the domain authority from the old domain automatically be inherited by the new domain, even if there are a lot of links?
John explained that there are two aspects here. On one hand, if you’re moving from one website to another, and you use the redirects to move things over using various tools (such as the change of address tool in Search Console), then this helps us to really understand that everything from the old domain should just be forwarded to the new one.
That’s a situation where, as much as possible, Google will take everything from the old domain and just apply this to the new one.
The other aspect is that Google does look at things like canonicalization on a per page basis. For canonicalization, they examine many factors that come in. For example, the following may all play a role:
- Internal linking
- Rel=canonical on the pages
- External links
What could potentially happen in more edge cases is that, if Google sees many external links going to the old URL, and maybe even some internal links going to the old URL, Google may actually index the old URL instead of the new one.
Because from Google’s point of view, it begins to look like the old URL is the right one to show and the new one is maybe more of a temporary thing.
Because of this, John recommends that when you do a site migration from one domain to another, is not only to setup the redirect, and not only use the change of address tool, but also go and try to find the larger websites that were linking to your previous domain and see if they can update those links to your new domain.
Basically, just make sure that everything you do is aligned with ensuring that Google can focus on the new domain rather than on the old one.
This happens at approximately the 42:03 mark in the video.