I've been asked several times about PDF files (like those made with Adobe Acrobat) and SEO.
My advice? Use MS Word (or Wordperfect) not Acrobat. For reasons that I can only describe as being stupid to the extreme, only the latest (and really expensive) versions of Acrobat save links within the PDF document. And not if you use the printer driver function (aka PDFMaker), which is what most people use. Only the latest Acrobat Distiller lets you do this, and it's slow. I've also had formatting and crashing issues with Distiller.
If you have no links in your document, it gets considered to be a dead end or honeypot by the search engines. Not good.
Also, if you take an image or scan and make it a PDF, then it's a PDF of an image or scan, so it's not spiderable except as a file name (just like an image).
You can test to see if a PDF is from an image or a text file if you can load it into Acrobat reader and highlight the text and copy it. If you can't, it's probably a picture of text, and is not spiderable.
There is another twist. If you make a document with links in it, then turn that document into a PDF using the PRINTER function (which is usually how Acrobat and other related PDF makers do things) then all the links are lost. They are lost as soon as the file prepared to be sent to the printer device.
Oh, they will show up in the Acrobat Reader as a clickable link if the whole link exists (but not if it has anchor text), but this is the reader turning it into the link, not an actual link in the document that a spider could follow.
The only way to create a PDF that is indexable as text and has real links with anchor text (in short, the only SEO-friendly method) is to use a method where the links are processed within the document, not on the way to the printer. This is usually the case where, for example, you create the PDF using the "Save as" feature rather than the "Print to" feature.
This is built into MS Word/Office 2007 and above (if you download the free PDF/XPS plugin) and in the WordPerfect Suite. There are a couple of other options, as well. But most are not SEO-friendly.
The following software WILL convert/keep MS Word links during PDF conversion:
- Office 2007 (with plugin)
- WordPerfect Office (version 9 and above)
- createpdf.adobe.com (but ONLY if you check "Create Tagged PDF" in the non-free version)
- Adobe Acrobat (any version up to 7)
- PDF from image = bad
- PDF from printer driver = bad
- PDF processed within the text editor and saved = good.