In the SEO world, there are two ways to fail. One — not doing enough. The other, far more destructive — doing the wrong things. Risky backlinks belong to the second category. In the best case they simply don't get counted. In the worst — they trigger a manual action or algorithmic penalty that pins your site down for months.
In this article we cover the 7 link types Google detects automatically with SpamBrain, how to tell if your site is already affected, and what to do if you've already been penalized. This isn't theory — it's a health warning for your site.
1. Links from PBNs (Private Blog Networks)
Private blog networks built solely to sell links
A PBN is a strategy of buying expired domains with high DR and building lightweight blogs on them whose only purpose is to sell links. In Google's eyes this is the most aggressive form of policy violation.
2. Link Farms
Sites linked to each other in a long loop
Unlike PBNs which exist to sell — Link Farms are sites that all link to each other. It used to work; today SpamBrain detects the pattern via complex graph algorithms.
3. Comment Spam
Links in comments on blogs, forums, and videos
This used to be the classic technique — leaving comments with a link in bulk. Today most comment platforms add nofollow automatically, and Google detects comment-spam patterns.
4. Sitewide Footer Links
A footer link that appears on every page of a site
In the past, people thought "if I get a link from a 1,000-page site — that's 1,000 links!". That was true 15 years ago. Today Google counts it as one link, and sometimes as a flag for paid linking.
5. Irrelevant links
Links from sites in unrelated topics
If your site is about car rental — and you got a link from a cooking-recipes site — that's a flag. Google has measured "topical relevance" aggressively since the 2023 update.
6. Unmarked Paid Links
Paid links without rel="sponsored"
Google's guidelines are clear: every paid link should be marked sponsored or nofollow. In practice, if you buy links and don't mark them — you're at risk. You won't get penalized immediately — but if you're caught aggressively, the penalty will be heavy.
7. Aggressive anchor text
More than 15% of your anchors are exact match
Penguin (part of the core algorithm) measures the ratio. Aggressive anchor text is the strongest signal of manipulative link schemes. See the anchor-text strategy guide for healthy ratios.
How to tell if you already have a problem
Three signals that say "open GSC right now":
- An alert in Google Search Console under "Manual actions". The clearest signal — Google tells you directly.
- A dramatic drop in organic traffic with no other obvious cause. Check whether it lined up with a Google algorithm update (Google Search Status Dashboard).
- Loss of rankings on keywords you used to rank for. Weekly checks in Ahrefs / Semrush.
How to recover from a penalty
Step 1: identify the problematic links
Ahrefs > Backlinks > filter by low DR (under 15) and suspicious sites. Build a list of 100–300 risky links.
Step 2: try to remove manually
Reach out to the site owners and request the link be removed. Success rate: 10%–30%. Document every outreach — you'll need it if you go to disavow.
Step 3: Disavow Tool
Links you couldn't get removed — upload them to Google's Disavow Tool. Google will ignore them. Use only when sure — disavowing good links by mistake is harmful.
Step 4: Reconsideration Request
If it was a Manual Action — submit a reconsideration request in GSC. Explain what you found, what you fixed, and how you'll prevent it in the future. You'll get a response within weeks.
Recovering from a penalty takes 3–9 months on average. Sometimes the site returns to where it was; sometimes it stays below — depending on how long the penalty was active.
FAQ
How do I know if a link is a PBN?
Check the site in the Wayback Machine. If it used to be a completely different site, that's a red flag. Also, look up the IP — if many other sites on the same IP look similar, it's probably a PBN.
Can a single bad link trigger a penalty?
Almost impossible. Penalties come from patterns — 50+ bad links, aggressive anchors, etc. But one very bad link from a very bad site can hurt traffic to a specific page.
Is link exchange a risky link?
No — when done correctly. Triangular exchange between relevant sites at sensible volume is not a manipulative link scheme. Risk starts when you exchange in volume, with irrelevant sites, or with aggressive anchors.
How fast does SpamBrain catch a problem?
In 2026 — weeks, sometimes days. SpamBrain runs continuously, not in isolated updates. The more aggressive your link program, the faster you'll be caught.