Are links between a subdomain and a root domain internal or external?

[unitedairlines]

We have a microsite on a subdomain that is kind of a community site that has articles posted to it several times per week. The articles are often relevant to topics covered on the root domain, so links are often included. My question is, are links between the subdomain and root domain considered internal or external? Also, how much of a difference does the location of the links make? For example, if we have a related links menu with links to the root domain is that good enough, or is it that much better to have the links embedded in the article text (toward the beginning of the article)?

[Chris.Menke]

A search engine considers a subdomain to be a different entity from the root domain and links to and from are considered external.  Don't be counting on those links from the subdomain to be doing much for the root domain, though, unless your root domain is a strong entity unto itself.  A few links from separate pages may be helpful but engines won't be oblivious to the fact that  their coming from the same IP address as the root domiain (as most subdomains are).

[Thos003]

Classic answer, ..."It depends."

At one time theses links would have been considered external. But Google has grown up and realizes that most of these are internal links. Maybe it had something to do with Hubpages using sub-domains to escape the panda.

While this article is not specific to your link graph, it may help to realize that google is on to this type of linking... http://googlewebmastercentral.blogspot.com/2011/08/reorganizing-internal-vs-external.html

However, the "it depends" can come into play when you don't own the domain, say wordpress.com. Those subdomains are likely treated very differently. Each subdomain on wordpress.com is unique it's authors. Perhaps this is why Google wants to push authorhship.

[ThompsonPaul]

In my experience, Carolyn, links between subdomain and primary get the worst of both worlds.

The search engines can clearly see that two sites are interrelated  so the links between them aren't entirely "natural". Therefore I don't  find the links carry the full amount of their influence across (not to mention the subdomain is usually far lower authority than the primary.)

On the other hand, the search engines still seem to consider subdomains as stand-alone sites which must earn their authority on their own, so they don't directly benefit from the halo of authority of the primary site.

See what I mean by  "the worst of both worlds"?

The blog post Thomas refers to is quite specifically only related to how links between subdomains and primary are reported in Google Webmaster Tools, so I'd be careful about extrapolating it too far into ranking factors. (Though in essence I agree with him that these types of links seem to function more like internal than external as far as value is concerned)

As far as the location of the links on the subdomain's page, typically links in menus & sidebars (especially if they are site-wide menus) contribute a smaller percentage of whatever influence they have than if they were a natural part of the content.

And from a user's perspective (which I prefer to think of first, before SEO considerations) it probably makes more sense to include the link to related info right in the article rather than making them go looking for it elsewhere on the page after finishing the article.

You've asked a good question, and it's answer really starts to get into the "art" part of SEO as few pure data points are viable to use when answering. Which will be why you will get a range of perspectives in the answers.

Hope that helps?

Paul

[Edited to add: If the microsite is so closely tied to the topics and purpose of the main site, it may be worth considering moving it to a subdirectory of the primary so the two sets of content can better support each other's rankings.]

[unitedairlines]

Thanks Paul! This is very helpful information!

[vidi78]

@ThompsonPaul

I've just go trough with your line " (not to mention the subdomain is usually far lower authority than the primary.)" so I want to know you are talking about Domain Authority or Page Authority?