PDFs are one type of document often found on websites and many marketers wonder how these can play into search engine optimization (SEO). When thinking about PDFs from an SEO perspective, there are few things to take into consideration.
First, search engines do index PDF files, and believe it or not, they can rank fairly well.
Links from PDFs to a website can actually be valuable. PDFs typically have fewer links (if any at all) and therefore, all SEO weight that could be passed from the PDF is transferred through those few links, if any are present. If the PDF is located on a site other than your own, and if there links pointing to your website from within the content of the PDF, these can be beneficial for your website, especially if keyword rich anchor text is used. (This is only the case if the other site does not restrict access to their PDFs.)
Also, keep in mind that if the PDF is shared among other websites, just like any other web page, they have the potential to be seen as duplicate content. When the search engines find duplicated content on more than one domain, the preferred one to display in the search results is often up to the search engines’ discretion.
That said, even though PDFs can rank well, it is generally not recommended to use PDF as targets for search. They have little to no navigation back to the website and as a result, they end up being dead ends for users as well as for search engines. They also tend to have a high bounce rate in the results pages because they involve downloading a file, which some searchers don’t want to do.
To target the content within a PDF for SEO purposes, it is best to create new pages of content on the actual website to target the main keyword of the PDF and include a link to download the PDF version. Often, the content will not be exactly the same as the PDF, so it will be less likely that one version will be filtered out by the search engines as a result of duplicate content. This also allows the visitor to download the PDF, if desired. As a best practice from a usability perspective, it is usually a good idea to restrict access to these files, so long as there is a page that supports the keyword targeted content. This can be done easily by making them all accessible under one directory such as /pdf/.
Browse around your website (especially the News, Press or Events sections) to see if you have any PDFs that could be utilized as a way to build out additional pages on your website. There could be more opportunities than you imagined to expand your keyword reach.