Last week I was reading about Google’s PageRank formula as it was originally created. As you probably know, PageRank is a numeric value which Google assigns to all the pages in its index, based on the incoming links to a page, to determine the relative value of a page.
Google founders Larry Page (recognize the similarity with PageRank ) and Sergei Brin stated in their original paper that a page need to be in Google’s index to pass on PageRank.
Want PageRank? Get indexed
That made me wonder if that’s still the case today. At first it seemed logical to me that a page needs to be known by Google to accumulate PageRank and to pass it on to other pages.
Google calculates PageRank on the total network of sites Google has in its index. From that point of view a non-indexed page can’t accumulate PageRank, because Google can’t determine the relative value the page. Or can it?
What about Robots.txt and Meta robots?
But what about pages which have the meta robots tag configured to not index the page but to follow all the links on it (noindex,follow)? And what about pages which are excluded from the index with the Robots.txt file?
With the group feature of LinkedIn I thought I might as well ask the question to some experts in the LinkedIn SEO group. At first people had the same reaction as I first did.
But I asked the same follow up questions as above. A very sound answer followed by Marie-Claire Jenkins:
She summarizes it nicely:
“NoIndex is a request to not show the page in the results. PR still passes. NoFollow, PR doesn’t pass but does accumulate”
Not indexed? PageRank still passes on!
If we have to believe what people like Wiep and Marie-Claire Jenkins are saying, than the answer to our question “Does a non-indexed page pass on PageRank?” would be ‘Yes’. And I think they are right.
A page could be not in a search engine index (or Google’s index for this matter) for many reasons. But people can still link to that page. So therefore it could accumulate PageRank.
Following the links
Of course those links need to be on pages which are indexed by Google, so Google will end up at the non-indexed page. Let’s assume it stays out of the index because it’s blocked by Robots.txt.
That means that Google won’t show the page in search results retrieved from its index, but it knows the links to and from that page. Therefore it can add this page to the PageRank calculations of the entire Google network of sites.
We actually need to rephrase what the definition is of being in Google’s index. I would opt for the following guideline:
“A page need to have an incoming link visible to Google to accumulate and pass on PageRank”
So, does a non-indexed page pass on PageRank? Yep, it does! (if the links to and/or from the page are visible to Google ).