Google and PDF Optimization
For those who don’t know much about the subject we should make it clear that Google CAN index content from a PDF file, meaning that links found in a PDF file do count and pass link juice. This has been verified by Google. It’s different for images as these will NOT be indexed unless they are within an HTML file.
According to them links in PDF files are the same as like links in HTML, passing link juice, authority and other signs of indexing. For those who don’t want their PDF files being indexed, all you need to do is add the attribute “nofollow” “noindex” to these files. Having already been indexed, you can remove these URLs from Google’s index using Webmaster Tools.
According to Google’s guide and my own experience PDF files can even rank above HTML pages with similar content, so it is a good idea to try or at least consider them as part of your SEO strategy.
Using PDFs as part of your link building will make your overall link building strategy look more natural.