Underscores in URLs are now Treated as Word Separators by Google

Till now, Google used to treat dashes and underscores in the URL differently. A dash (hyphen) between two words in the URL (i.e. keyword-phrase) would tell Google that those are two different words (i.e. keyword +phrase). In the past, an underscore between two words in a URL (i.e. keyword_phrase) would tell Google that those words are a single word (i.e. keywordphrase). Now both underscores and hyphens in the URL are treated as word separators.

One key development that Matt shared with the audience was that underscores in URLs are now (or at least very soon to be) treated as word separators by Google. That's great news, because it historically hasn't been that way. Back in 2005, Matt stated that Google did not view underscores in URLs as word separators. That meant that in a URL like http://www.mysite.com/iphone_review.html Googlebot couldn't "see" the words iphone or review. Instead it read iphone_review as one word. I wouldn't recommend targeting "iphone_review" as a keyword, as I doubt anyone will be including an underscore in their Google query.

So it used to be--until now--that any benefit that you would have gotten by having a keyword-rich URL was negated by the use of underscores separating those words. TypePad and Movable Type blogs were particularly affected by this, as by default, underscores were used instead of hyphens. This new change in the Google algorithm should make bloggers using the TypePad service or the Movable Type blog software (and anyone else using underscores in their URLs) very happy, as I anticipate their Google traffic will be going up.

A few other highlights from Matt's talk that you may find interesting:

• Matt claims that Google treats URLs with a query string the same as static URLs. Caveat: as long as there are no more than two or three parameters in the URL, that is! Put another way, you won't take a hit in your Google rankings if you have a question mark in your URL; just don't have more than two or three equals signs in the URL.
  
• Matt stated that the number of slashes in your URL (i.e. the number of directories deep your page is) isn't a factor in your Google rankings. He went on to say that although it doesn't matter for Google, it is rumored to matter for Yahoo and MSN (Live Search). Matt addressed this because I specifically asked the question from the audience.
  
• According to Matt, the file extension in your URL won't affect your rankings. So it's inconsequential whether you use .php, .html, .htm, .asp, .aspx, .jsp etc. The one extension you should avoid for your Web documents? .exe.
  
• Matt stated it was myth that Google uses its status as a domain registrar to access domain registration data to use it as a ranking signal. According to Matt, being a registrar doesn't grant one special access to other registrars' customer data. Note that Matt didn't state whether Google is or isn't using WHOIS data as a signal. I believe they are.
  
• When asked about how to get one's blog into Google News, Matt shared one of Google's requirements for inclusion: the blog must have multiple authors. So those of you wanting your blog showing up in Google News results, I hope it's a group blog!