Dashes, Underscores, URLs, SEO and Humans

If you browse around the web some looking for search engine optimization (SEO) tips and techniques you are bound to run into the a dash is better than an underscore in a URL “rule”. This has always bugged me since underscores give better visual separation of the words, which I tend to equate to easier reading for us humans.

Way back in 2005, Matt Cutts from Google explained that Google treats dashes and underscores differently, and why. That is great and all, but 2005 is three years ago — an age in web time.

In August 2007, pretty much every big search engine confirmed that they treat dashes and underscores the same. Well, everyone except Google, which hinted that they were on their way. I was unable to find any updates on the subject since then.

Now, we’ve been running underscores in our URLs since sometime in mid 2005 and we’ve always had decent results with our pages being indexed appropriately. To clarify this issue a little, I thought I would do some experimentation.

Taking my Firefox HTML Validator on Ubuntu Gutsy post from our blog as a test page, I fed the terms html, validator and gutsy into each of the following search engines:

• Yahoo
• Google
• MSN
• AOL
• AltaVista
• Ask.com

All of the search engines that highlight terms in URLs (all but AOL and AltaVista) seems to have no problem grabbing the words in the URL. Notice how my post is listed above a page that uses dashes instead of underscores. I guess it is possible the search engines don’t care about word separators when highlighting keywords, but it seems that dashes and underscores are functionally equivalent when matching pages.

So, should you go through and revamp all of your URLs from dashes to underscores? Probably not, but it’s worth thinking about when starting a new site. Spending time polishing the little aspects of your site can make the difference between a good and a great site.

Dashes vs. Underscores

I find that the underscore gives better visual separation since it lives beneath the baseline whereas dashes seem to make the words run together. Another interesting point it that a dash has a grammatical meaning, whereas an underscore is an invention stemming from underlining with typewriters.

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dashes_underscores_urls_seo_and_humans

Do you prefer dashes or underscores, and why?

If you enjoyed this post, you might want to check out one of my semi-related posts, HTML Title Tags Done Right.