We scan the HTML for 10 classic CSS hiding patterns used in PBN / spam SEO. Detect before purchase sites that already hide links, your future backlink would be condemned by association.
10 classic CSS patterns used in PBN / spam SEO: display:none, visibility:hidden, opacity:0, font-size:0 or 1px, text-indent with a very negative value (off-screen), position:absolute + left:-9999px, clip:rect(0,0,0,0), height:0 + overflow:hidden. Plus detection of suspicious class names (hidden-text, seo-text, hide-seo, and so on).
If the host page already hides links, two problems. First, Google detects this pattern and penalises the whole page, so your future backlink gets diluted into the penalty. Second, it's a behavioural signature of a PBN or spam marketplace. The publisher has clearly adopted these tactics, the site is probably already on Google's radar. Investing 100 € on this kind of page is a near-certain dead loss.
We only scan inline HTML (style="..." attributes and <style> tags). Sites that hide content through an external CSS file (.css fetched separately) are not covered, that would require fetching every referenced CSS resource and matching selectors. Even so, around 70 to 80% of amateur PBNs hide inline because it is simpler to template.
Not by default. These classes are used for accessibility to add context for screen readers (skip links, invisible labels). We only flag them when a link is inside. A "screen-reader-only" link that contains a commercial exact-match anchor is a stuffing pattern disguised as accessibility.
On the Nautilinks network, every site is manually validated before being listed. No PBN, no hidden text, no opaque marketplace.