If you have a big eCommerce site with lots of products, layered navigation can help your users to narrow down their search results. Layered or faceted navigation is an advanced way of filtering, by providing groups or filters for (many) product attributes.
In this filtering process, you might create a lot of URLs though. The reason for this is that the user can filter and thereby group items in many different ways. Those groups will all be available on separate URLs. So what should you do with all these URLs? Do you want Google to crawl them all?
Daniel Jacobsen sent us this question on the subject:
“Should I nofollow layered navigation links? And if so, why? Are there any disadvantages of this?”
Check out the video or read the answer below!
Layered navigation links
“The question is: “Why would you want to do that?” If you have too many URLs, so if you have a layered or a faceted navigation that has far too many options -creating billions of different types of URLs for Google to crawl – then probably yes. At the same time, you need to ask yourself: “Why does my navigation work that way?” And, “Can we make it any different?” But in a lot of eCommerce systems that is very hard. So in those cases adding a nofollow to those links, does actually help to prevent Google from indexing each and every one of the versions of your site.
I’ve worked on a couple of sites with faceted navigation that had over a billion variations in URLs, even though they only had like 10,000 products. If that’s the sort of problem you have, then yes, you need to nofollow them and maybe you even need to use your robots.txt file to exclude some of those variants. So specific stuff that you don’t want to be indexed, for instance, if you don’t want color indexed, you could do a robots.txt line that says: “Disallow for everything that has color in the URL”. At that point, you strip down what Google crawls and what it thinks is important. The problem with that is, that if Google has links pointing at that version from somewhere else, those links don’t count for your site’s ranking either.
So it’s a bit of a quid pro quo, where you have to think about what is the best thing to do. It’s a tough decision. I really would suggest getting an experienced technical SEO to look at your site if it really is a problem because it’s not a simple cut-and-paste solution that works the same for every site.