PDF Links

This isn’t exactly groundbreaking and likely many of you already know this, but it came as news to me when investigating the question for a client recently, so I thought I would flag it for the benefit of anybody in the same epistemic position. Also as evidence that I don’t just sit here thinking about kittens all day.

Google has for a long while indexed PDF files and their contents. However, it seems to be less well known that Google not only follows links from within PDF files too, but that these links both flow PageRank and pass anchor text benefit. Various commentators I read differed on whether the links are devalued relative to an equivalent HTML link, but some benefit is certainly attainable.

(The subject came up because a certain client’s press release handling was recently centralised with its US arm, meaning that their new press releases were being hosted off-site and in PDF. This suggested an opportunity for happy international vampirism via links in the PDFs. Sadly, I was thwarted in this.)

The major downside to using PDFs seems to be that they acquire incoming links much less readily than the same content in HTML - Rand of SEOMoz claims that people are less than half as likely to link to a PDF, presumably because they are still seen as inaccessible. Hmm. At least one of our ebook creators has been paying attention to PDF linking anyway; the recent iCrossing “How to Start Blogging” ebook contains a single highly targeted link back to icrossing.co.uk. Limiting the number of links is useful in a PDF as nofollow cannot be used to selectively direct link benefit - recent news about nofollow notwithstanding!

I was also interested to read that (allegedly) no duplicate content penalty is assessed against HTML that duplicates the content of an available PDF; perhaps we should take the time to offer any new iCrossing ebook in both formats?