Should you block the indexing of your empty category pages?

What does 'concentrating link flow' really mean?

When Mueller talks about concentrating link flow, he refers to the concept of PageRank sculpting. The idea is to prevent Googlebot from following certain links to direct crawl budget and link equity towards strategic pages.

On an e-commerce site, empty categories absorb crawl without generating user value or conversions. By applying nofollow on these internal links, you signal to Google that it can ignore these dead ends. The bot then focuses its resources on your active categories and product listings.

Why does Google call this impact 'marginal'?

The term 'marginal' is not trivial. Google has gradually diminished the effect of PageRank sculpting over the years. Today, nofollow is treated as a hint, not an absolute directive.

In practical terms, on a site with 5,000 to 20,000 URLs, optimizing a few dozen empty categories will not change your positions. The crawl budget is really only critical on very large sites (millions of pages), where every URL counts. For others, Google already crawls enough to index your strategic content.

What is the difference between noindex and nofollow in this context?

Mueller specifically talks about nofollow on internal links, not noindex. A noindex prevents the page itself from being indexed, while nofollow prevents the link leading to it from being followed.

For empty categories, the choice depends on your strategy. If these pages are temporarily empty but intended to fill up, a provisional noindex via meta robots may suffice. If you want to keep the page indexable but reduce crawl to it, nofollow on internal links is more suitable. The most radical approach is complete blocking via robots.txt, but then you lose all flexibility.

• Internal Nofollow: reduces the flow of PageRank and crawl to the page, but it remains accessible and indexable
• Noindex: removes the page from Google's index while allowing crawl and following of outgoing links
• Robots.txt: completely blocks crawl, Google does not even see the content of the page
• The impact remains limited on standard-sized sites, as indicated by Mueller
• PageRank sculpting via nofollow has become a hint, not a strict command

Is this recommendation consistent with observed practices?

Let's be honest: PageRank sculpting via nofollow is a relic of a bygone era. Since 2009, Google has changed how nofollow affects the flow of PageRank. Previously, a nofollow link allowed you to 'keep' the juice for other links. Today, that juice is simply lost.

In practice, A/B tests show that the effect of internal nofollow is almost imperceptible on sites with fewer than 50,000 pages. The gains observed often come from other optimizations carried out in parallel. [To be verified]: Mueller provides no numerical data to back the real utility of this practice, even if deemed marginal.

What are the risks of an overly aggressive application?

Multiplying internal nofollows can create dead ends in your linking structure. If an empty category today fills up tomorrow, and all your links to it are nofollow, Google will take longer to discover it and index the new products.

Another trap: some CMSs automatically generate links to empty categories in filters, faceted navigation, or breadcrumbs. Applying nofollow without prior audit can fragment your architecture. You risk creating content islands poorly connected to the rest of the site.

In what cases can this optimization make sense?

On very large e-commerce sites (100,000+ URLs), every optimization counts. If your crawl budget is saturated and Search Console indicates discovered but uncrawled pages, then yes, cleaning up empty categories becomes relevant.

However, even in this case, noindex is often more effective than nofollow. It directly removes the page from the index without relying on Google's interpretation of hints. The real lever is not to generate links to those pages in the first place: adjust your templates to hide product-less categories in navigation.

How do you identify empty categories that merit action?

The first step is to extract the complete list of your categories via a Screaming Frog or Oncrawl crawl. Cross-reference this data with your product base to identify categories with zero products. Then, check in Search Console if these pages generate impressions or clicks.

If they never appear in the SERPs and receive no organic traffic, indexing is pointless. But if they capture impressions on brand queries or strategic terms, keep them indexed and feed them rather than block them.

What method should you apply based on your site's size?

On a site with fewer than 10,000 pages, investing time in nofollow for empty categories is counterproductive. Google is already crawling your site extensively. Focus on the quality of your internal linking and the relevance of your anchors.

Between 10,000 and 100,000 pages, a targeted audit can identify quick wins. Use a conditional noindex (meta robots tag) on empty categories, with a script that automatically removes the noindex once a product is added. It's more reliable than nofollow.

Beyond 100,000 pages, the crawl budget becomes critical. In this case, a combined strategy makes sense: noindex for empty categories, removal of unnecessary internal links, and optimized pagination. Nofollow remains a secondary tool in this arsenal.

Should you automate or handle manually?

Automation is the only viable approach at scale. Setting up your CMS to apply an automatic noindex on product-less categories avoids omissions and adapts in real-time to stock fluctuations.

For complex sites with seasonal variations (fashion, sports), this automation becomes essential. An empty 'swimwear' category in winter should stay indexable if you plan to reactivate it in spring. A too-rigid system penalizes you.

Given the complexity of these technical arbitrations and the potential impact on your visibility, support from an experienced SEO agency can save you time and avoid costly mistakes. Crawl budget auditing, conditional implementation of indexing directives, and long-term monitoring require specialized expertise that few internal teams possess.

• Crawl your site to list all categories and identify those without products
• Check in Search Console if these pages generate impressions or traffic
• Prioritize conditional noindex over nofollow for empty categories
• Automate management through your CMS to avoid manual errors
• Monitor server logs to measure the real impact on crawl
• Reserve this optimization for sites with more than 50,000 pages if the crawl budget is saturated