Are blog comments a ranking factor?

Usually when there is a question mark in the title of an article the answer is no. In this case the answer is probably yes. But with most things in SEO it’s hard to give a firm confirmation. In this post I’ll look at the arguments for and against comments being a ranking factor.

To be clear; I’m talking about blogs allowing comments on article. Not the linkbuilding tactic. Assuming the site doesn’t publish obvious spam comments would this actually help a website rank higher?

Argument FOR comments being a ranking factor

1) Shows a website has a healthy thriving community (according to Google)

Jennifer Slegg from TheSEMPost basically asked this exact question to Garry Illyes (@methode) from Google. In response Garry said that comments show there is a community on a website. And a “healthy thriving community” is an indication of quality. Which in turn is a positive ranking signal for Google.

In general if we see that there’s a healthy, thriving community on a site, that can help a lot […] it feeds into general quality. Say, there’s good content, 5 points, great links from great pages, 2 points, thriving community, 1pt […] that wasn’t a stack rank. The points I gave are random

2) It increases the word count of the page

Please don’t understand me wrong — I’m not suggesting word count is a ranking factor. But it has been well researched* that longer content tends to rank higher. This is a case of longer content being on average better quality and therefor performing better (correlation).

If a search engine is evaluating content for quality they look at things like topical strength, relevance, synonyms, reading level and outgoing links (and citations). Comments can all help with this since comments will usually phrase things in a different way, ask relevant questions and use a different tone of voice. More words = more longtail content.

* A study done by Ahrefs showed a very positive correlation to longer form content and research from Backlinko showed a similar trend.

Arguments AGAINST comments being a ranking factor

1) No independent proof

Besides the confirmation by Google no independent ranking factor study has ever mentioned blog comments. There have been plenty of studies on ranking factors by companies such as Moz, Ahrefs and Semrush. Not once have studies on millions of websites and queries found a correlation between blog comments and rankings.

Of course this doesn’t completely rule out comments as ranking factor. After all, it’s hard to find something if you’re not looking for it. But many smart marketeers and webmasters are looking for an advantage in the SERPS and none of them have found and published extensive proof.

2) Poor quality content can bring overal quality down

If not properly moderated, internet comments are known to be low quality. This includes comments that don’t add anything to the conversation (“Great post!”) but also actual low quality content with grammar and spelling errors.

A common SEO strategy is to prune out thin and low quality content because this might help other pages rank. Wouldn’t the average comment bring down the quality of a page?

3) It’s very easy to abuse

There is a good reason search engines are so secretive about ranking factors. Webmasters are known to abuse methods to the extreme to gain an advantage in Google. This has been the case with most link building tactics, on-page information like <h1>‘s and even the massive growth of HTTPs can partially be attributed to Google making it a minor ranking factor. It’s not hard to imagine that search engines shy away from easy to abuse ranking signals.

Comments would be a very easy to abuse ranking factor. Any webmaster can load fake comments into their database and make them look slightly plausible.

4) There are better ways to see if a site has a community

A site having an active community is a good metric of quality. But comments are far from the best way to test that. Even the most active blogs don’t get more than 1 to 5 percent of readers commenting.

Combined social metrics of Moz blogpost
This Moz article got almost of 1400 shares but only 29 comments.

A far better way to see if there is a community? Social media. Most sites and business are active on social media. Seeing how much activity their updates get is a great way to tell the credibility of a site. The reason search engines (probably) don’t do this is because of again how easy to abuse it is.

Bonus: Turning off comments will lead to more social signals

On this blog I specifically chose to turn of comments because I wanted to move the conversation to Twitter. Not so much for a ranking reason but an increase in social signals (shares, replies) might be a ranking factor on it’s own.

Lets speculate and say a big blog turns off comments (losing a potential ranking boost) and instead encourages social sharing. Even if this only increases shares by 10% this increase could negate the loss and be a bigger ranking signal on its own. Of course social signals being a ranking factor is a much debated topic on its own.

My opinion

Before writing this article and doing this research I thought the idea of comments being a ranking factor laughable. I’ve changed my mind. When done right comments I believe comments give a positive ranking signal. How much weight it has? That’s an even harder question to answer.