You've gone through every page of your website and added your target keywords to your title tags, heading tags, meta tags and body content – that means you're done with your search engine optimization, right?!
Guess again! In fact, if you only optimize the HTML pages on your website, you're missing out on a key opportunity – the ability to optimize the PDF files that reside on your site as well.
If you've never done PDF optimization before (and don't worry, a lot of people haven't!), check out the following tips on how to get the biggest search benefit from these hidden files:
Traditional SEO for PDF Files
In a lot of ways, PDF files are treated like any other page on your website. The search engines are able to crawl them and index their content, as long as you follow certain rules. These include:
Creating your PDF files using text-based programs. Although Adobe InDesign and other graphics-based programs can produce great-looking PDFs, they may prevent your files from being indexed correctly in the search engines. For this reason, it's important to use text-based programs like Microsoft Word to create any PDF files that will be deployed on your site.
Optimizing your PDF file correctly. As with web page optimization, there are a few specific ways you'll want to include your target keywords in your PDFs for maximum SEO benefit:
- Specify your “document properties”. When creating PDFs you should have the opportunity to add relevant title, author, subject and keyword tags, depending on the program you use to create your files. Make sure that each of these fields is optimized with your target keywords, just like you would the meta tags on a traditional web page.
- Make use of keyword-rich headline tags, image caption tags and body content. Just like on HTML web pages, the locations in which your target keywords appear and the frequency with which they're used helps the search engine spiders to understand what your file is all about and where it should be ranked in the SERPs.
- Use appropriate SEO file naming conventions. On a standard website, you'd name your HTML and image files according to your target keywords to improve your page's SEO, and PDFs should be no different. Titling your PDF as “my-target-keyword.pdf” may give your file the slight advantage that allows it to rank highly in the blended SERPs, resulting in increased traffic and exposure for your site.
Placing your PDFs strategically on your site. If you bury your PDFs too deeply in your content pages or – worse yet – upload them in compressed .ZIP files, they won't be crawled by the search engines. For maximum value, link to PDFs from your home page or make it very obvious that you're linking to a PDF file if you must include them on sub-pages within 1-2 clicks of your homepage.
Obviously, as with traditional web pages, it's important not to go overboard and over-optimize your PDFs. Use your target keywords strategically, but sparingly, in a way that provides value for your readers without appearing too spammy to the search engines.
The Role of PDFs in Mobile Discovery
Another important thing to consider when it comes to using PDF files on your site is how mobile discovery platforms might identify vital information about your business.
In a recent article on Entrepreneur.com, we took a look at how Siri, Apple's new voice recognition software, could impact the importance of traditional local SEO. Basically, if people come to rely on programs like this to identify local businesses for their needs (in the article, we used the example of asking Siri to call a cab after a night on the town), they could ultimately wind up bypassing the traditional SERPs entirely.
Obviously, traditional websites, review sites and social profiles will all continue to have their place in the search hierarchy, but the important thing for business owners to consider now is how programs like Siri might access information on their sites. Right now, it's not entirely clear how Siri analyzes information when determining which results to direct a user to, but it's safe to say that the algorithm isn't yet as sophisticated as it could be – which might mean that the information contained in PDF files isn't being analyzed correctly.
So if you, as a local business owner, have important information like restaurant menus, open hours, directions and so on stored in PDF files on your site, it might be a good idea to place this information on the home page of your site as well in order to improve access by Siri and other similar programs that are sure to be coming in the future.
Using PDFs to Improve Off-Page SEO
Another extremely under-utilized way to improve your site's SEO with PDFs is to use these files as link bait in order to spur the creation of high-quality inbound links to your site. Generally, PDFs are high-value documents – whether they're lecture slides packed with detailed information, guides to completing specific processes or other valuable descriptions – which makes them ideal candidates for drawing links back to your site.
One way to do this is to post your PDFs on file sharing websites like Scribd or SlideShare. Not only will deploying your PDFs on these sites help to build traffic to your site through increased brand awareness, you'll receive a backlink to your site every time these PDFs are shared on other sites (assuming, of course, that you followed the rules described earlier about optimizing your files for search engine discovery).
It's also a good idea to encourage the social sharing of your PDFs. Since we now know that social signals are a ranking factor in Google's and Bing's search algorithms, we can use our PDFs to generate social shares that point back to our websites. Depending on the quality and value of your PDF, this could be as simple as seeding your PDFs on your favorite social networking sites and watching them go viral as people share your files with friends and family members.
If this all sounds like a lot of work, don't worry – it isn't necessary to complete every step listed above in order to improve the SEO of your PDFs. However, keep in mind that because these key SEO principles aren't widely known or utilized by most site owners, they could represent a valuable opportunity for your business to distinguish itself in the search engines by implementing these techniques ahead of your competitors. So give these ideas a try – you might just be surprised by how much you can improve your site's SEO with just a little effort at optimizing your PDFs.