What is Comment Spam?

Spam comments can be a problem for any website that enables users to contribute to discussions. Blogs, forums, review sites, and social media platforms all attract them.

Most comment spam comes from bots: automated scripts that crawl the web for open comment forms and post the same spam to every form they find. The goal is almost never to join the conversation.

What a spam comment looks like

A typical spam comment flatters you while ignoring what you wrote. Picture a comment from an author named “cheap designer bags outlet” that reads “Great post! Very helpful. Check out my site for amazing deals,” followed by a link to a store that has nothing to do with your article. The tells:

• Generic praise that could sit under any article on the web
• A keyword or business name in the author field instead of a person’s name
• An off-topic URL in the comment text, the author’s website field, or both

Why spammers post comment spam

The motive is the link. Spammers post comments to build backlinks they hope will raise their own site’s search rankings, and to pull referral traffic from your readers. Some links go further and lead to scams or malicious sites.

Google’s answer is link qualification. Its Search Central documentation recommends marking links in user-generated content, comments included, with rel=”ugc”; the older nofollow attribute is also acceptable. Either tells search engines to pass no ranking credit through the link, which removes most of the incentive to post it.

What comment spam costs your site

The obvious cost is trust. A comment section full of junk makes visitors doubt the content above it, and even link-free spam derails real discussion. The less obvious cost is search visibility: user-generated spam falls under Google’s spam policies, and sites that violate them “may rank lower in results or not appear in results at all.” Moderating comments protects your rankings, not just your readers.

How to prevent comment spam

You don’t need to shut down comments to beat spam. Four measures reduce it dramatically:

• Hold comments for moderation, or at minimum hold any comment that contains a link, and publish only what a human approves.
• Run an anti-spam plugin. Akismet comes bundled with WordPress and checks every comment against spam patterns and IP addresses learned from the 100+ million sites it protects (Akismet’s own count, August 2026).
• Add a challenge before the form submits, such as a CAPTCHA or a simple question. Even a small hurdle discourages automated submissions.
• Limit who can comment: require registration, and close comments on posts that have gone stale.

No filter is perfect, and the usual casualty is a legitimate comment flagged by mistake. Review your spam or moderation queue periodically and restore any false positives before you delete comments permanently.

For setup steps, see our guide to stopping WordPress comment spam with Akismet. Before you disable comments entirely, weigh the trade-off: keep them open with moderation where discussion adds value, close them on posts that have gone quiet, and turn them off completely only if you never engage with readers. Spam prevention alone isn’t a reason to lose genuine engagement.