You have 200 backlinks. Sounds great. But 50 might be helping your rankings, 50 are doing nothing, and 100 could be hurting you.
A single link from an authoritative, relevant site outperforms a hundred directory links. A handful of toxic links can tank rankings faster than you’d expect.
What Makes a Backlink High Quality?
Google evaluates each backlink asking: “Is this a genuine endorsement or manipulation?”
Relevance
The most underestimated factor.
A link from a cooking blog to your SaaS product is weird. Google knows it. A link from a tech review site makes sense.
Relevance works on three levels:
- Site-level - Is the linking site in your industry?
- Page-level - Is the page topic related to yours?
- Contextual - Does surrounding text naturally lead to your link?
Authority
Authority is cumulative trust. Sites like NYT or Wikipedia have massive authority. A new blog with three posts doesn’t.
Tools measure this differently (Domain Rating, Domain Authority, Trust Flow), but they’re all approximating Google’s trust signals.
The catch: authority without relevance is overrated. A link from a high-authority news site in an irrelevant sponsored post won’t move the needle like a moderately authoritative site in your niche.
Link Placement
Where your link sits matters.
Good: Main body content, naturally integrated into sentences, early in the article.
Weak: Footer links, sidebar widgets, author bios, comment sections, “resources” pages with 500 other links.
Google distinguishes editorial links from template links.
Link Type
Dofollow links (without rel="nofollow") pass ranking signals.
Nofollow links (rel="nofollow", rel="sponsored", rel="ugc") tell search engines not to count the endorsement.
If your paid links are all nofollow, you’re paying for traffic, not SEO value.
Anchor Text
The clickable text signals what your page is about.
Natural: Brand name, check out this guide, partial keyword matches, bare URL.
Suspicious: Exact-match keywords like best cheap running shoes buy now, identical anchors across many links.
Red Flags: Low-Quality Backlinks
Irrelevant Sites
A backlink from a Romanian gambling site to your accounting software? Red flag.
Spammy Sites
Sites that exist to sell links or host scraped content. Thin content, aggressive ads, random topic mix, visible spam. Links from these can actively hurt you.
Sitewide Footer/Sidebar Links
One domain linking from every page through footer credits? Google largely ignores these. One domain, one vote.
Non-Indexed Pages
If Google can’t find or won’t index the linking page, the backlink passes zero value.
This happens with:
noindexmeta tagsrobots.txtblocks- Bot detection serving different content to crawlers
- Login-required pages
Toxic Patterns
Links from PBNs, link exchange schemes, obvious paid placements, irrelevant foreign-language sites, or penalized domains can trigger penalties.
How to Audit Your Backlink Profile
Step 1: Export Your Backlinks
Pull from Google Search Console (free, limited) or Ahrefs/SEMrush/Moz (comprehensive, paid). Export source URL, target URL, and any metrics.
Step 2: Verify Links Exist
Links disappear. Pages get deleted. A report from three months ago might be 20% out of date.
Step 3: Check Link Attributes
For every existing link:
- Dofollow or nofollow?
- Any redirect chains?
A “dofollow” link might have quietly switched to nofollow.
Step 4: Check Page Accessibility
Even if a link exists and is dofollow, the source page must be accessible to search engines.
Check for:
- Noindex tags - Google ignores the page, ignores your link
- Robots.txt blocks - Prevents crawling entirely
- Bot detection - Different content served to crawlers vs. humans
Verify Link Quality at Scale
Manually checking hundreds of backlinks is tedious and error-prone.
Backlink Checker Pro automates verification. Upload your report (PDF, CSV, Excel) and instantly verify:
- Link existence - Does the link actually appear on the page?
- Follow status - Dofollow, nofollow, sponsored, or UGC?
- Page issues - Noindex tags, bot blocks, accessibility problems
Common Issues That Kill Backlink Value
page_is_noindex
The linking page has a noindex meta tag. Google won’t index it, so your backlink doesn’t exist from an SEO perspective.
Common on staging sites, thank you pages, and login-required content.
page_blocks_bots
The source page uses bot detection. Your link might be visible in a browser but invisible to Google.
blocked_by_robots
The page is disallowed in robots.txt. Search engines won’t crawl it.
Link Not Found
The simplest problem: the link was removed, the page restructured, or it was never there. Happens more with outsourced link building than people admit.
The Real Cost of Not Auditing
You hire a link building service. 50 links/month for six months = 300 backlinks.
But when you check:
- 40% are nofollow (you paid for dofollow)
- 15% of pages have noindex tags
- 20% of links no longer exist
- 10% are from irrelevant sites
That’s 85% providing minimal or zero value. You paid for 300, you’re getting maybe 50.
Quality-Focused Strategy
Relevance Over Authority
A link from a highly relevant DR 40 site often beats an irrelevant DR 80 site.
Verify Before Paying
Check deliverables before making payments. Sample immediately, full verification before final payment.
Monitor Existing Links
Quarterly audits catch removed links, nofollow switches, degraded sites, and new technical issues.
Disavow Toxic Links
If you find clearly harmful links (spam sites, obvious PBNs), consider Google’s disavow tool. Be careful - disavowing legitimate links hurts you.
How do I check if a backlink is high quality?
Evaluate relevance (is the source related to your niche?), authority (domain trust level), placement (main content vs footer), link type (dofollow vs nofollow), and anchor text (natural vs over-optimized). Use a backlink checker to verify technical factors like page indexability.
What's the difference between dofollow and nofollow?
Dofollow links pass SEO value to your site. Nofollow links (marked with rel="nofollow") tell search engines not to pass ranking credit. Nofollow links can drive traffic but don't directly boost rankings.
Can bad backlinks hurt my SEO?
Yes. Links from spam sites, link farms, PBNs, or irrelevant foreign sites can trigger penalties. Use Google's disavow tool for clearly toxic links, but only for obviously harmful ones.
How often should I audit my backlinks?
Full audit monthly. Verify new backlinks immediately when received from agencies. Deep review of important links quarterly - links can be removed or switched to nofollow without notice.
Why do some backlinks exist but provide no SEO value?
Technical issues: the page might have a noindex tag, be blocked by robots.txt, use bot detection that hides content from crawlers, or have the link set to nofollow.