Could Google hide one of your sites if they look too similar?

What does 'similar sites' really mean for Google?

Google does not duplicate results it deems redundant for the user. Similarity is not limited to duplicate content — we are talking about distinct sites, with unique content, but sharing too close an architecture, editorial angle, or purpose.

Specifically, if you operate two domains selling hiking shoes with different texts but with an almost identical structure, geographical targeting, and positioning, Google may decide to show only one domain for a given query. The second is not penalized — it is simply omitted to avoid perceived redundancy.

Is this omission a disguised penalty?

No. The omission is neither a manual filter nor a punitive action. It is an algorithmic choice for diversity in results. Your second site remains indexed, can appear for other queries, and incurs no penalties.

The nuance is important: a penalized site sees its rank drop. An omitted site for similarity remains eligible, but Google prefers to display a competitor or another of your domains deemed more relevant for that specific query. It’s a logic of deduplication at the SERP level.

Why doesn't Google provide a clear threshold for similarity?

Because there is no single metric. Similarity is assessed by a set of signals: theme, related entities, internal link structure, backlink profile, user intent covered, even the same owner identified via Analytics or Search Console.

Google applies machine learning to detect patterns of 'series' sites. No public threshold will be communicated — that would open the door to gaming. A seasoned SEO knows that the line is blurry and depends on the context of the query.

• Distinct sites without duplication: ranked independently if sufficiently differentiated
• Very similar domains: only one may be displayed per query, with no penalty for the others
• Same owner: not a blocking criterion if the sites are genuinely unique in content and intent
• Algorithmic similarity: assessed by a bundle of signals, not a public checklist

Does this statement align with on-the-ground observations?

Yes, largely. SEOs have observed for years that Google filters redundant results, even between distinct domains. When a brand operates multiple e-commerce sites targeting the same product, it is not uncommon for only one to dominate the SERPs, with the others appearing only for very specific queries or at the bottom of the page.

However, the definition of 'very similar' remains subjective. Sites with unique content, different angles but a same owner may end up competing internally without always understanding why. [To be verified]: Google asserts that it treats 'unique' sites separately, but the line between 'unique' and 'too similar' is painfully lacking transparency.

What signals does Google use to detect similarity?

Mueller does not detail, but on-the-ground experience points to: shared backlink profiles, pages linked to the same entities, almost identical HTML structure, same technical footprint (CMS, server, CDN), same owner identified in GSC or Analytics.

A telling counterexample: two sites from the same owner, one in B2B and the other in B2C, with unique content but a close theme, can be treated separately if user intent diverges sufficiently. Google seeks to map intent — if your two sites address the same intent, you risk omission. Otherwise, you coexist.

In what cases does this rule not apply?

If your domains target clearly distinct geographies, languages, or segments of intent, you should not face omission. A classic example: a .com and a .fr with localized content, not translated in a trivial manner, are treated separately without issue.

On the other hand, if you create multiple domains with content spinning, paraphrased texts, or cloned architecture, you fall exactly into the use case targeted by this rule. Google will not penalize — it will simply ignore your perceived duplicates.

What should you do if you manage multiple domains?

First, ask yourself the strategic question: do these domains have a distinct purpose for the user? If the answer is 'to optimize SEO by multiplying presences', you are probably in the at-risk zone for omission.

If each site serves a different intent, audience, or geography, clearly differentiate the editorial angle, structure, and link profile. Do not clone the hierarchy. Do not target the same keywords with the same angle. A concrete example: a site dedicated to trail running, another to alpine hiking — even under the broad same theme, but with distinct audiences and content.

How can you check that your sites are not omitted?

Run targeted queries for which you should rank with multiple domains. Use the site: operator to force the display of each domain and compare with a regular search. If a domain never appears naturally while being indexed and relevant, you probably have a case of omission.

Search Console can also alert you: low impressions despite good positioning on certain queries is a signal. Cross-check with crawl and indexing data — if everything is green on the technical side but traffic is not picking up, similarity with another domain is a serious lead.

What mistakes should you absolutely avoid?

Do not set up 'satellite' domains with recycled content, even paraphrased. Google no longer needs to see strict duplicates to understand that two sites are saying the same thing. Machine learning analyzes semantic intent, not just n-grams.

Avoid linking your domains heavily together with common footers or sidebars. You sign your network and make detection easier. If you must link, do so editorially, contextually, and sparingly.

• Audit the real differentiation between your domains (content, angle, audience)
• Check for the absence of cloned HTML architecture or identical technical patterns
• Test visibility with and without site: operator on targeted queries
• Analyze backlink profiles to avoid overly marked common footprints
• Monitor impressions in GSC for unexplained drops
• Localization and customization of content if multiple domains target nearby geographies