An outdated Google index category for low-value pages, now merged into the main index.
I know it feels confusing when SEO terms change, but I am here to make things simple and clear for you. We need to look at an old idea to understand how Google works today and get you those better rankings. I am sharing smart, practical tips that explain this old concept and improve your website now.
Understanding: What is Supplemental Index (Google’s Old Term)?
Back in the day, Google had two main parts to its search list: the main Index and the Supplemental Index. I think of the main Index as the VIP list where all the important, high-quality pages went. The less important, weaker pages were put into the Supplemental Index, meaning they hardly ever showed up in search results.
The History of the Term
Google used this term to explain why some pages were crawled but not given full ranking power. The pages in the Supplemental Index were often duplicates, very old, or had very little content. I remember this term causing a lot of panic among website owners years ago.
The Modern Reality
Google does not use the term “Supplemental Index” anymore, and they say they have one big index. However, I still see Google treating pages differently based on their quality and importance. Your goal should always be to make sure all your valuable pages are considered high-quality and fully crawlable by Google.
CMS Impact: Avoiding the “Supplemental” State Today
WordPress & Webflow: Quality Control
With flexible CMS like WordPress or Webflow, I tell clients to use tools to stop low-quality pages from being indexed. I always check things like category archives with no content or old tag pages that offer no value. You have great control to prevent Google from treating these pages like old supplemental content.
Shopify & Wix: Template Issues
I know Shopify and Wix sometimes create duplicate pages or large amounts of automatically generated pages, which can cause issues. For example, product filter pages can accidentally flood the search index with low-value content. I use platform-specific SEO apps and settings to stop Google from seeing these pages.
Custom CMS: Indexing Freedom
A custom CMS gives you total control, which means you are fully responsible for what Google finds. I recommend implementing clear noindex tags on any pages that are necessary for the user but offer no search value. You have the power to direct Google only to your most valuable pages.
Industry Applications: Focus on Core Value
Ecommerce & Local Businesses: Product Focus
For an online store, I want Google to focus all its attention on your key product and service pages. Pages like “out-of-stock” items or tiny policy pages should be kept out of the main index to save your crawl budget. You must guide Google toward the pages that make you money.
SaaS & Blogs: Content Quality
If you run a SaaS company or a large blog, I advise you to regularly check for thin or outdated articles. Pages with just one paragraph or very old, inaccurate information are the modern equivalent of supplemental content. I suggest updating or deleting them to lift the quality of your entire site.
Every Site: Technical Clean-up
Regardless of your industry, I believe technical clean-up is key to avoiding low-quality indexing. I check broken links, fix crawl errors, and simplify the site structure so Google understands your priorities. You need to present only your best content to the search engine.
Frequently Asked Questions (FAQ)
Does the Supplemental Index still exist today?
Google officially states that the term and the two-part index do not exist anymore. I find it useful to think of it as a quality barrier, where low-quality pages are still indexed but rarely rank in search results.
How do I know if my pages are seen as low quality by Google?
I check Google Search Console for “Indexed, though blocked by robots.txt” or look for pages with very few clicks. A low-quality page might also show up only for very specific, long-tail searches and never for core terms.
What should I do if a valuable page is not ranking?
First, I check the page’s content to make sure it is high-quality, unique, and long enough. Then, I focus on building internal links to that page from other strong pages on your site. This tells Google that the page is important to you.
