Domains, Subdomains and Microsites

Domains, subdomains and microsites is a topic where the industry speaks confidently and Google's documentation is restrained. There is no described mechanism of "passing authority" from a subfolder or a subdomain, no timings such as "two to three months" or "nine months", and no rule that "a subfolder is better in 90% of cases". What there is instead: trade-offs in upkeep, measurement and geotargeting, which can be compared honestly. This lesson covers what is documented, what remains opinion, and how to choose a structure on practical grounds.

It rests on the guide to international sites and on the description of a site move.

What is documented about the "edges of a site"

Two consequences of where the edge runs are documented outright.

• Crawling. The crawl budget guide says that subdomains are treated as separate sites and have separate crawl budgets. For small sites that barely matters — see the lesson on discovery and crawling.
• Measurement. In Search Console a domain property includes all subdomains and multiple protocols, and if you need to limit data by a path segment such as example.com/es/ or example.com/en/, you create a URL-prefix property. The practical conclusion: a section in a subfolder can be measured on its own, while subdomains fall into the domain-wide sample.

Looking at data section by section is what folder performance does.

The trade-offs in Google's documentation

The guide to international sites lays the options out as pros and cons, not as "best" and "worst":

Note what the table does not contain: the words "authority", "weight" or "reaches the top faster". The options are different balances of cost and control. On language versions see also the hreflang documentation and international visibility.

What stays industry opinion

These widespread claims do not appear in the documentation, so they cannot be presented as rules:

• "a link to any page lifts the whole domain" and "a subfolder passes all of the link weight";
• "a subdomain gets authority in two to three months", "a new domain needs nine months", "in a year the site will be five times more authoritative";
• "a subfolder is better in 90% of cases".

That does not mean the opposite is true. It means these figures are someone's observations on particular sites, not a property of Google. When choosing a structure, rely on what can be checked: cost, measurability, technical constraints and the target audience.

The domain zone

Here the documentation is specific. A country-code domain (ccTLD) is used as a signal of geographic association, with caveats: Google treats some vanity ccTLDs, such as .tv and .me, as gTLDs, because users and site owners frequently see them as more generic than country-targeted. For everything else: unless ICANN lists a top-level domain as a ccTLD, Google treats any TLD that resolves through the IANA DNS root zone as a gTLD. So new zones such as .shop or .blog are ordinary gTLDs with no country association.

The consequence for a site on a generic zone: if it wants to target users in a particular geographic location, it should explicitly set a country target using the methods in the same guide. Server location sometimes signals the audience too, but it is not a definitive signal, because many sites use CDNs or are hosted in a country with better infrastructure.

Microsites and separate domains

A microsite is a separate site, which means a separate Search Console property, a separate crawl budget, and separate work on structure and links. Those are costs, not a promise of quick results.

When a campaign ends and the microsite has to be joined to the main site, what is documented for a move applies: 301 and other permanent redirects don't cause a loss in PageRank, and a redirect is a strong signal that the target should become canonical. The same guide sets realistic expectations: expect temporary fluctuation in ranking; for medium-sized sites it can take a few weeks or more for Google to gradually show the new URLs instead of the old ones, and a move can be made in sections. The details are in the lesson on site migrations, and whether the redirects are right is what the redirect check shows.

How to choose a structure

1. Audience and product. Does the same person use the blog and the shop? Then there is nothing to separate them on. The principles of a single structure are in the lesson on information architecture.
2. Measurement. Do you need data by section separately? A subfolder is measured with a URL-prefix property; subdomains only as part of the domain or as a property of their own.
3. Technology. Do you need different servers, different platforms and independent releases? That is an argument for a subdomain — and it is in Google's table.
4. Geotargeting. Do you need a firm tie to a country? Then a ccTLD, accepting the cost and the one-country limit.
5. The cost of being wrong. Any decision will have to be changed through a move, which per the documentation means weeks of fluctuation. So a structure is chosen once, carefully.

The domain name: practical considerations

These are no longer Google's requirements but convenience for people: the name should be unique, easy to type from dictation and to remember, without hyphens and double meanings. Registering related zones protects against imitation. None of this bears on ranking.

Mistakes

• Building a decision on the "2–3 months" and "9 months" figures as if they were documented.
• Treating a subfolder as "always best": in Google's table it has its own cons.
• Creating separate domains for what serves the same audience.
• Choosing a zone for an SEO advantage: new gTLDs are ordinary generic zones.
• Not setting a country explicitly on a generic zone when geotargeting is needed.
• Abandoning a microsite with no redirects instead of joining it to the main site.

What comes next

The next lesson is about URL structure: what addresses should look like and what to do with them.