URL structure is one of the most important issues in SEO. However there are confusions about URL creation practices, and many different opinions. I had recently an interesting conversation with few SEO experts and I did some dipper research about this problem.
Let’s look at the leaders. Wikipedia uses underscores for all subpages. We can consider this website in many cases as a model for SEO friendly websites. However, wiki has so many incoming links, that the structure of URLs doesn’t really play significant role in search engine visibility. If you take a look other big websites (cnn, nyt) you can notice that URLs there are build by using dashes.
Let’s go deeper. I was browsing an internet and looking for opinions about dashes vs. underscores and I found a news from cnet.com which announced that Matt Cutts at WordCamp 2007 (news from July 2007) mentioned that Google sees underscores and dashes in the same way. It used to be not like that. Back in 2005, Google did not view underscores in URLs as word separators. That meant that in a URL like www.royaldeerdesign.com/web_design.html Googlebot couldn’t see the words web or design. Instead it read web_design as one word. However, as Matt announced it used to be like that and it is not anymore.
To confirm that information I decided to go to the source – Google’s documentations. I found the guide about URLs structures. I have found there kind of confusing information. The official Google guide says “We recommend that you use hyphens (-) instead of underscores (_) in your URLs.”
Frankly speaking I don?t really relay on Google guides. Mainly, because the frequency of updating this guide is much smaller than updates in Google’s search engine algorithm.
So, I went one more step further. I just googled many phrases and check results. I have found that in results there were pages both with underscores and dashes, and there were no clear winner. Results suggest that Google reads in the same way underscores and dashes as separators.
The conclusion: URLs structure is an important issue. However, even if really dashes are better that underscores, this element of SEO has such a small impact on the position of the website in search results that in 99% we shouldn’t really care about that issue. It is better to focus on links building, mete tag optimization and content writing. Many of my clients has URLs with underscores, and changing the structure of all inks to dashes would be not profitable investment. The impact on SEO (if any at all) will be indeed invisible and impossible to measure because of its marginal importance. However, I decided to use dashes in all future projects we will develop. Even if I don’t agree in 100% and I didn’t really proof that dashes are better that underscores, it will never hurt to follow Google’s official guide and the biggest websites. Those websites (such as mentioned before New York Times) have very close relationship with Google and they have SEO advices from the source. So, if you have an established website, don?t try to change your URLs, it is really wasting of your time and money. It is better to just focus on other SEO issues. However, in feature projects try to implement dashes instead of underscores. You know, just in case, plus dashes seem to look better visually