There has been a lot of information floating around the Internet regarding dashes and underscores. A writer at CNET reported that he heard Matt Cutts speak at WordCamp 2001 in July and Matt said that underscores in URLs were either â€œnowâ€ or â€œsoon to beâ€ treated as word separators by Google.
However, on August 10th Barry Schwartz at Search Engine Land reported the Matt Cutts was informing everyone that reports of Google treating underscores as word separators is not yet happening.
Matt Said: “I wouldnâ€™t consider it a completely done deal at this point. But note that I also said if youâ€™d already made your site with underscores, it probably wasnâ€™t worth trying to migrate all your URLs over to dashes. If youâ€™re starting fresh, Iâ€™d still pick dashes.”
So, Dashes and Underscores Are Not the Same
On August 10th Matt Cutts discussed this issue in his blog and said that they had someone looking into it, but it was not a done deal. On August 25th Matt discussed the issue again and recommended people continue to use dashes
Why Does This Even Matter?
You need to see an example to understand. If your URL says http://blahblah/purple_widgets Google will not see the word â€œpurpleâ€ or â€œwidgetsâ€. It would see purple_widegts as one word, so essentially someone would have to search for â€œpurple_widgetsâ€ to find you in the SERPs.
What About the Other Search Engines?
On August 2nd Barry Schwartz reported that he contacted the other search engines to see how they handled underscores and dashes/hyphens. He said that Yahoo, Microsoft and Ask.com confirmed that they do treat underscores the same as dashes.
Web sites need Google to do well, so obviously optimizing for Google is very important. The best thing we can do, for now, is to continus to use dashes/hyphens as word separators.