Definition
A Comment Spam Bot is a computer program designed to automatically publish comments containing links on large numbers of blogs, forums, and community sites. These bots exploit open comment forms to post generic messages (often generated by spintax) with links to sites being promoted. The most well-known tools in this category are ScrapeBox, GSA Search Engine Ranker, Xrumer, and RankerX. They work in several stages: target URL collection (harvesting), CAPTCHA solving (via services like 2Captcha or Anti-Captcha), then automated comment posting. Google deployed the rel=nofollow attribute in 2005 specifically to counter comment spam. In 2020, the rel=ugc and rel=sponsored attributes strengthened this protection. Sites affected by comment spam can receive a Google manual action for 'user-generated spam'. Protection solutions include Akismet, reCAPTCHA, manual moderation, and closing comments on older articles.
Key Points
- Automated software that mass-posts comments with links
- Primary tools are ScrapeBox, GSA SER, Xrumer, and RankerX
- Google created the nofollow attribute in 2005 specifically against comment spam
- Affected sites risk a manual action for 'user-generated spam'
Practical Examples
Massive ScrapeBox attack
A spammer configures ScrapeBox to post 10,000 comments overnight on WordPress blogs. The comments are all similar ('Great post, thanks for sharing!') with a link in the signature. 95% are blocked by Akismet.
Bot with CAPTCHA solving
An advanced bot uses the 2Captcha service to automatically solve comment form CAPTCHAs, bypassing sites' primary protection. The cost is a few cents per solved CAPTCHA.
Detection and cleanup
A blog owner discovers 3,000 spam comments awaiting moderation, all from different IPs. They install Akismet, enable reCAPTCHA v3, and apply rel=ugc to all comment links.
Frequently Asked Questions
Install an anti-spam plugin (Akismet for WordPress), enable reCAPTCHA v3, enable comment moderation, apply rel=ugc to comment links, close comments on posts older than 30 days, and use a web application firewall (WAF) like Cloudflare.
No. Nearly all comment links have been nofollow or ugc since 2005. Google ignores these links for ranking. Additionally, penalties for artificial links make this practice counterproductive. The rare sites without nofollow are quickly identified and corrected.
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Last updated: 2026-02-07