Do comments really affect Google rankings?

Why does Google make this distinction between direct and indirect factors?

The nuance here is essential to understanding how the engine works. A direct ranking factor explicitly impacts the algorithm — such as backlinks, quality content, or loading speed. Comments do not have this privileged status.

They contribute to the volume of indexable textual content. Google scans comments as it scans any block of text on the page. If this text contains keyword variations, user questions, related terms, it broadens the page's semantic field. Result: the page may match a wider range of queries, especially in the long-tail.

What type of content do comments actually provide?

A typical comment introduces natural language, rephrasing, sometimes questions that users are truly asking. Let's take an article on "how to install WordPress." Comments can contain "database error during installation," "file permission issues," "incompatible server configuration." All variations that the main article may not cover word for word.

This is where the indirect effect occurs. The page becomes relevant for peripheral queries, even if the author hasn't explicitly optimized for those terms. But be careful — this is not systematic. A comment that says "thank you, great article!" adds absolutely nothing to ranking.

To what extent is this contribution measurable?

Google does not provide any figures. Mueller refers to it as “not a magical factor,” a typically vague statement. In practice, the observed impact varies greatly depending on the volume and quality of comments. A page with 200 comments rich in industry vocabulary will likely have a measurable advantage over an identical page without comments.

However, if those 200 comments are spam, empty one-liners, or duplicate content, the effect can be negative. Google may consider the page as overloaded with low-quality content, which degrades user experience and, consequently, ranking. Moderation thus becomes a full-fledged SEO lever.

• Comments enrich the semantic field of the page with natural user vocabulary
• No direct boost in the algorithm — the effect occurs through the coverage of long-tail queries
• Quality outweighs quantity — spammy comments can degrade the overall page signal
• Moderation is an SEO act — filtering out weak comments improves the signal-to-noise ratio
• The impact varies by sector — forums, tech blogs, e-commerce sites see different effects

Is this statement consistent with what is observed in the field?

Yes, and it is one of the few positions from Google that aligns with empirical observations. On blog or forum-type sites, it’s frequently noted that pages with active comments capture positions on queries that the main content does not target. A typical example: an article on "best WordPress caching plugin" also ranks for "WP Rocket conflict with WooCommerce" thanks to a comment detailing that issue.

However, there is a selection bias that shouldn't be ignored. Pages that generate a lot of comments are often already well-positioned, attracting traffic and receiving strong engagement signals. It is difficult to tell whether it is the comment that improves the ranking, or if it is the ranking that generates the comments. The causality is unclear — and Google does not clarify it.

What nuances should be considered regarding this statement?

Mueller says, “it’s not a magical factor,” which implies that one should not overestimate the effect. Let's be honest: no site will move from page 3 to page 1 solely because of comments. It’s a marginal boost, on specific queries, often niche ones.

Furthermore, Google does not specify how it weights comments' content in relation to the main content. One can assume that a comment has less weight than a paragraph of the article body — but nothing confirms this officially. [To verify]: does Google apply a depreciation coefficient to comment blocks, as it does for sidebar or footer content? No public data on that.

In what cases does this rule not apply?

If comments are generated by bots, filled with spammy links, or completely off-topic, Google can completely ignore them — or even treat them as a negative signal. An e-commerce site with fake reviews or purchased comments risks manual or algorithmic devaluation.

Another edge case: comments with nofollow or blocked in the robots.txt. If Google cannot crawl or index the comments, they contribute nothing to ranking. Some CMS block indexing of comment sections by default to prevent spam — in this case, the effect described by Mueller is null.

What should you do concretely to optimize the impact of comments?

First, enable comments on strategic content. If you have articles that already perform on main queries, comments can help them capture long-tail variations. But there's no need to force it on transactional or institutional pages that naturally generate no engagement.

Next, implement a rigorous moderation. Systematically reject empty comments (“great article!”), spam, and off-topic ones. A plugin like Akismet or CleanTalk can automate part of the work, but a human eye is still essential to filter edge cases. The goal: ensure that every validated comment provides usable information, a question, or feedback.

What mistakes should be absolutely avoided?

Never let duplicate or generic comments accumulate. Google can detect low-quality UGC content, and if your page becomes a dumping ground for spam, it can lose positions. Worse: if comments contain outgoing links to dubious sites, you risk being pulled into a spam network.

Another trap: blocking comment indexing by reflex. Some SEOs fear duplicate content or spam and slap a noindex on the entire comment section. The result: you deprive yourself of the effect described by Mueller. If you moderate correctly, there is no reason to noindex — on the contrary, you waste semantic potential.

How can you check if comments truly contribute to ranking?

Use Search Console to identify long-tail queries that generate impressions or clicks. Compare these queries with the content of your comments. If you see matches — for example, a query like “500 error during migration” and a comment mentioning that exact problem — it’s an indication that the comment is playing its role.

You can also test by temporarily disabling comments on a test page and observing traffic changes over 4-6 weeks. If positions on long-tail variations drop, it means comments had an impact. But be careful — this type of test is noisy, full of biases, and hard to isolate from other factors.

• Enable comments on content with high engagement potential (blogs, tutorials, guides)
• Moderate manually or via anti-spam plugin to ensure quality content
• Systematically reject empty, generic, or off-topic comments
• Check in Search Console for long-tail queries captured through comments
• Do not block comment indexing if moderation is active
• Monitor the quality of outgoing links in comments (regularly check with Screaming Frog or similar)