Tedster at WebmasterWorld asks an excellent question. In short, he wants to know if links ever truly disappear from Google's link graph. Let me quote him:
We've all seen URLs "fall out" of the index at times. But does Google still use those URLs as part of their web graph when they iterate link juice? Or is their web graph confined only to those URLs that can be retrieved as search results?
I'm sure that once a URL is crawled, the data is not just gone if the URL is no longer in the visible index - Google wouldn't throw away data, right So I wonder if the publicly visible pages that can be shown in the SERPs at any one moment are only a subset of the full web graph that Google uses for PageRank calculations - and others, too.
This idea came to him after midnight, on Sunday morning. I suspect many SEOs have thought of this in passing but never really put the concept down on paper.
Yea, I am sure they never go away in terms of Google storing them somewhere. But do you think they continue to pass on link juice after they are long gone?
Moderator, lammert, replied:
One of my sites has about 50% of the pages with the "noindex,follow" robots attribute. They are not visible in the SERPs, but experience is that link juice just happily flows. That may not be fully representative for links which "fall out" of the index, but the juice graph of Google consists of definitely more than just visible URLs.
What do you think? Take our poll:
Ever is a strong word, so let's say non-penalized links that simply just end up going away. Do they pass even a tiny bit of link juice? If so, answer "No."
Forum discussion at WebmasterWorld.