Faceted Navigation: SEO and Facets

Faceted navigation, when done well, can help customers find what they are looking for quicker and in a more satisfying way. This is good for business and for the bottom line. After all, customers can’t buy what they can’t find.

I’ve been interested in faceted navigation for some time now. I’ll be giving a workshop on faceted navigation at the Euro IA conference in Paris at the end of September. (There’s still room if you want to attend. You don’t have to attend the conference to attend the workshop). In preparing for my workshops, I continued to be amazed by how much detail and complexity there is in the design of faceted navigation systems, particularly when dealing with real-world implementations. And there’s lots of room left for creativity and innovation, too.

One issue that’s recently come to my attention is that of SEO and faceted navigation. Now, I’m not an SEO expert in any way—in fact, I know very little about the field. Still, I wanted to cover some of the aspects of facetted navigation and SEO in a blog post based on research I did on the web. Please provide constructive criticism in a comment if I miss something or get something wrong.

The basic problem is this: facets are fundamentally polyhierarchical—infinitely so, or so it seems. In a system of faceted filters for search results of products, for instance, there can easily be millions of possible combinations.

Search engine crawlers don’t like this. It slows them down und eats up crawl bandwidth. Worse, some search engines might start seeing redundancy and think it’s some kind of spam. They then give up.

If you have a facetted navigation system on your site, it may be difficult to get it indexed effectively or indexed at all. But it’s not impossible—it just takes a bit of extra thought and planning from the beginning.

From surveying what others have said about how to deal with this, I’ve put together a simple list of what appear to be the top approaches to consider. Combinations of the below techniques generally improve the situation, as well: if you can do the top three, you’re probably in good shape.

1. Use a unique URL for each page, particularly product pages.
   Strive to create static URLs, even if they primarily parameter-driven. This advice comes from Rand Fishkin at SEOmoz.org in a Whiteboard Friday video on faceted navigation. Having a static URL allows search engines unique identify a page and index it.
   
2. Use a standard, topical hierarchy as a main navigation.
   Search engine crawlers like hierarchy. Having a primary path for them to index helps greatly. Include this hierarchy in the URL, as well, and strive to keep the navigation shallow. This advice comes from Matt Cutts, head of the Webspam team at Google. In an interview, Matt  says:

“While faceted navigation can be good for some users, if you can decide on your own hierarchy how you would categorize the pages, and try to make sure that the faceted navigation is relatively shallow, those can both be good practices to help search engines discover the actual products a little better.“

I believe the screen shot below—from HomeDepot.com—shows this, to some degree. Regardless of the order of selection of filters, the topical hierarchy always comes first in the breadcrumb and in the URL. In Figure 1, I selected Grills first, then a price category from $100-$200, and then Propane Grills—in that order. Both the breadcrumb and the URL force the category selections together, however. In this case, Propane Grills was inserted into the breadcrumb ahead of the price range, despite having selected the price range first. The human-readable category hierarchy in the URL is the second element, as well, which should help SEO.

Figure 1: Faceted Navigation on HomeDepot.com

3. Publish an XML sitemap of your entire site with directory style URLs.
For a company like Endeca, a leading provider of faceted navigation solutions—their “guided navigation“ system—SEO is a challenge they’ve come across long ago. And, accordingly, they’ve done quite a bit with SEO and faceted navigation. In addition to the above points, Rob Swint of Endeca recommends publishing an XML sitemap of your site. He outlines this approach along with others in the article “Three Techniques for Maximizing SEO.“

4. Other approaches
I also uncovered a few other approaches that didn’t seem to have widespread approval or acceptance. Some seem like workarounds and may have negative side effects, as well. Still, you might want to consider the following techniques. Again, this is not a recommendation, so please research them carefully:

1. 1. Examine search logs to see what people are searching for, and then create gallery pages or sub-pages for them.
   2. Add “nofollow“ attributes for faceted navigation links. It seems like the prevailing opinion, however, is against this. Using “nofollow“ is more of a workaround than a solution.
   3. Keep basic sorting functions out of the mix. To do this, track the sort with AJAX and/or via the user’s cookies. If you take this approach to an extreme, you could also do the filtering on the front end AJAX.

Done right, facets can let you create more landing pages than you could by hand, addressing long tail searches better. And, as mentioned at the beginning of the post, there are user benefits as well. While SEO and faceted navigation can be tricky, it’s not impossible to overcome. Please research the above approaches before implementing them.

Other articles:

“Facets As A Navigational & SEO Powerhouse” by Jamie Sirovich

“The New Natural Search Spam” by Brian Klais

Tags: faceted navigation, Facets, seo