PDF links - What is their value?

[superclown2]

Has anyone ever done any research upon the relative value of incoming links from a .pdf document, as against a conventional web page, I wonder?

[tedster]

PDF files themselves can accumulate PageRank (at least the PR server does respond with a number) so the implication seems to be that the filetype is treated like the more ordinary html filetypes. However, I wouldn't be surprised to see a difference between an image-based PDF that needs OCR to be read, and a text-based PDF that holds "straight" links.

It's been a long time since I tested PDF links directly, years in fact. Back then, links in PDF documents were definitely used for URL discovery, and they also seemed to help ranking. But I never pinned down whether PR was transferred at a "normal" level or not.

[internetheaven]

Has anyone ever done any research upon the relative value of incoming links from a .pdf document, as against a conventional web page

Yes ...

... but why do you want to know? Is there a story or eventual purpose to finding out the answer?

But I never pinned down whether PR was transferred at a "normal" level or not.

Did this one middle of last year but as I did not expect Pagerank passing to change dependent on doc type I suppose I wasn't really paying attention to that. I think the poster wants to know if seeking out PDF links will give him a boost the same way that people awkwardly tend to think .edu links given them an extra boost.

[superclown2]

Thanks tedster and internetheaven for the thoughts. The reason I am asking is because I've noticed that top scoring sites very often have a mix of html and pdf links and this could be viewed as a logical decision by search engine designers. And yes I do seek out .edu links for a very good reason - they tend to last longer.

[AnkitMaheshwari]

Has anyone used WMT's Fetch as Googlebot for an PDF link? What text (data) Google takes from a PDF file?

In my case it is giving very abstract characters (like '?' in black rhombus) throughout the file.

[phranque]

i would suggest you read the Matt Cutts Interview by Eric Enge [webmasterworld.com] and related discussion on this topic.

[tedster]

WMT's Fetch as Googlebot for an PDF link

Interesting idea. I know when I simply copy/paste text from a PDF document, depending on the font there can be all kinds of unusual distortions. For example, ligatures such as "fi" may get picked up as an "f" alone. And extra spaces get inserted within a word - I assume because of font kerning. I'm going to give that question some research time.