Comment spam
Black hat. Against Google’s spam policies. Risks a manual action or a ranking drop. White, grey and black hat SEO compared
What is comment spam?
Comment spam is posting promotional links in blog comments, forum posts, guestbooks or user profiles, usually automatically, to gain backlinks or traffic. For the person posting, it is link spam: Google’s policy names forum comments with optimised links in the post or signature. For the site hosting it, it is user-generated spam.
Most comment spam is posted by bots, with generic praise (“Great post, very helpful!”) and a keyword-rich name or link. It also shows up as spam profile pages and fake forum accounts. Because most platforms add rel="ugc" or rel="nofollow" to comment links, the links rarely pass value anyway.
Why comment spam matters for SEO
If you run a site with comments or a forum, unmoderated spam can earn you a manual action even though you did nothing wrong. Google expects site owners to manage user-generated content.
The white hat alternative for getting links is to take part genuinely in communities and earn links through link building. For hosts, it is moderation and rel="ugc" on user links.
Risks of comment spam
- For the spammer: links ignored, and possibly an “Unnatural links to your site” manual action.
- For the host site: a “User-generated spam” or “Site abused with third-party spam” manual action.
- For the host site: spam pages diluting quality and linking to harmful sites.
- Brand damage when spam mentioning your business appears across many sites.
How to stop comment spam
- Turn on moderation or hold first-time comments for approval.
- Use anti-spam filters and CAPTCHA on comment and sign-up forms.
- Add rel="ugc" or rel="nofollow" to links in comments and profiles; most platforms do this by default.
- Noindex or limit new user profile pages until users have a track record.
- Delete existing spam, then request review if you have a manual action.
Comment spam example
Name: Best Cheap Car Insurance
Comment: Very informative article, thanks for sharing! Check my site for more information.
(Link to an insurance comparison site, posted on a knitting blog.)
Comment spam FAQ
Do blog comment links help SEO?
Almost never. Most are nofollow or ugc, and Google names optimised comment links as link spam.
Can spam comments get my site penalised?
Yes, if there is a lot of it. Google has manual actions for user-generated spam and for sites abused with third-party spam.
Related SEO terms
User-generated content (UGC) is content created by a site’s users rather than its owners, such as reviews, comments, forum posts and Q&A.
rel="ugc" is a link attribute for links inside user-generated content, such as comments and forum posts, signalling the site does not vouch for them.
Link schemesBlack hat
A link scheme is any attempt to create links mainly to manipulate rankings, such as buying, swapping or automating links, which is Google’s link spam.
A nofollow link carries rel="nofollow", asking search engines not to pass ranking credit. Since 2019 Google treats it as a hint, not a rule.
Manual action (Google penalty)
A manual action is a penalty a Google reviewer applies when a site breaks its spam policies, demoting or removing pages until the issue is fixed.
Black hat SEOBlack hat
Black hat SEO is the use of tactics that break search engines’ spam policies, such as paid links, cloaking or keyword stuffing, to rank faster.