Editorial Note:

Originally written in [2005-2006], we’re republishing this article for context. At the time, Google had only just begun openly addressing blog comment spam. Today, in 2025, Google handles spam differently through advanced systems like SpamBrain and ongoing link spam updates. For the latest perspective, see our 2025 update on comment spam penalties.

Google Comment Spam Penalties in 2025: What You Need to Know

Quick Take: Blog comment spam is still around in 2025, but Google is much better at detecting and devaluing it. The penalty is less about “manual actions” now and more about algorithmic filters that quietly strip spam links of any ranking value.

How Google Handles Comment Spam Today

• SpamBrain technology: Since 2021, Google’s AI-driven system (SpamBrain) has been flagging and neutralizing unnatural links, including those hidden in comment sections.
• Link Spam Updates: Major updates in 2021 and 2022 made it clear: paid, manipulative, or irrelevant links—whether in comments or not—won’t pass PageRank.
• Automatic devaluation: Most comment spam links don’t hurt your site’s rankings anymore; they’re simply ignored. But if you allow your comment sections to be overrun, it can still signal low quality to Google.

Best Practices for Webmasters in 2025

1. Keep moderation on: Manual approval or smart filters (like Akismet or AI moderation tools) are still essential.
2. Use rel="nofollow" or rel="ugc": These attributes tell Google you’re not vouching for user-submitted links.
3. Maintain quality control: A clean comment section signals trustworthiness, while a spam-cluttered one can hurt user experience and indirectly harm SEO.
4. Don’t over-block: Thoughtful, relevant comments with links can add value. The key is moderation, not blanket suppression.

Final Word

Back in 2008, Google was only starting to talk tough about comment spam. Fast forward to 2025, and the game has changed. Comment spam links don’t work, and letting them through only damages your community’s trust. Keep your filters sharp, use rel attributes correctly, and focus on genuine discussions. That’s the only way comment sections add value today.

Originally written in [2005-2006],

I recently heard from a bird (actually, it was a beard, an Andy Beard, to be precise) that Google has introduced a penalty for blog comment spamming. As it usually happens, Google won’t admit to being a late bloomer in any issue regarding web usability. Accordingly, the tone of the original post (published by Adel Saoud and Paolo Petrolini on the Google Webmaster Central Blog) implied that Google already applied ranking sanctions for comment spamming and that this message is just an informative update. Truth of the matter is, Google is probably just starting to take action against abusive links posted in the comments section of blogs.

What does it all mean?

Long story, short, your blog relevancy is affected by the links posted in your post comments and if you do not manage to tidy up that particular section, you will suffer TrustRank penalties and ultimately drop in the rankings. I have to agree with Google on this, it makes sense, up to a point. But first, let’s look at the official arguements, quoted straight from the horse’s mouth (or, in this case, the GWC):

• “Abusing comment fields of innocent sites is a bad and risky way of getting links to your site. If you choose to do so, you are tarnishing other people’s hard work and lowering the quality of the web, transforming a potentially good resource of additional information into a list of nonsense keywords”
  True enough. A blog’s comments section is a space designed for on-topic interaction and dispute. A comment box stuffed with irrelevant links not only ruins the user experience, it also downgrades the actual article to which it comments.
• “Comment spammers are often trying to improve their site’s organic search ranking by creating dubious inbound links to their site. Google has an understanding of the link graph of the web, and has algorithmic ways of discovering those alterations and tackling them”
  This might just be a bluff on Google’s part, in an effort to ward off any potential spammers, by reaffirming its position as the web’s ultimate relevancy arbiter. In truth, Google probably has little control over the quality of links posted within the comment section of a blog and the comment spam detection system is probably just in its infancy state.
• “Having original and useful content and making your site search engine friendly is the best strategy for better ranking”
  Here we may have actually stumbled upon the real stake of this message. Introducing a blog comment filter in the ranking algorithm might just be another one of Google’s efforts to limit the SEO bad boys’ arsenal.

What can we do about it?

Most blogs feature intelligent spam filtering solutions (speaking strictly from WordPress experience), but there still isn’t a 100% guaranteed method of absterge comment spammers from  your blog permanently. In the post’s conclusion, Saoud and Petrolini were kind enough to offer some suggestions to zealous webmasters who want to limit spammers’ access to their system and, consequently protect their precious rankings:

• “Disallow anonymous posting”
  Fair enough. Providing minimum information (e.g. a nickname and an email address) shouldn’t be too much of a hassle for your potential commentators. However, this method has revealed its vulnerabilities, with the advent of Black Hat automation software.
• “Use CAPTCHAs and other methods to prevent automated comment spamming”
  Being an adversary of the dreaded CAPTCHA, I can not applaud this suggestion, especially since it is just as vulnerable to the above mentioned threat. So why stress your visitors with a cacographic abomination, when you can just as effectively ask him/her to provide minimum identification?
• “Turn on comment moderation”
  There are still people who disable comment moderation?
• “Use the “NoFollow” attribute for links in the comment field”
  I usually encourage adding the “NoFollow” attribute to uncontrollable outgoing links, but this can prove to be a problem, especially if you want to monetize your blog (hint: affiliate marketing). You can sacrifice a lot of link love this way and it is very unlikely that hardcore spam freaks will be discouraged by the “NoFollow” attribute, assuming they know what that even is.
• “Disallow hyperlinks in comments”
  No. No. No.
• “Block comment pages using robots.txt or meta tags”
  Again, risky territory, especially for those webmasters who try to cash in on their ranking positions for certain keywords (hint: affiliate marketing, once again)

My own two cents

Although the obvious benefits of waging war against comment spamming can not be denied, this new take does raise some questions. Like where does Google draw the line between a spammer and a harmless marketer, trying to add valuable input to a post and to promote his own website in the process? Or where are the battle lines drawn? Will quality matter or will the deciding factor be quantity and chance, in the end? And last, but by no means least, there is something to be discussed about the practical application of the comment spam filtering. Needless to say, Google’s warning targets only webmasters who host comment spams on their blogs and not the spammers themselves. This makes sense, since it would be damn near impossible to chastise a website for link spam on one blog if it runs an entirely legit link-building strategy the rest of the time. In addition, Andy Beard makes an interesting assertion at the end of his report of the GWC announcement, asking what if a competitor was trying to sabotage your ranking by spamming your blog’s comments section?

Whether the comment spam penalty adds value to the user’s online experience will be determined by time and the adaptability of the community. It all starts out as a good idea, but then again, so did communism…