Matt Cutts gave Digg & Wikipedia a nice piece of news last week at Wordcamp 2007. During the conference Matt was offering tips on search engine marketing to WordPress bloggers and explained that Google is starting to treat underscores in URLs the same as hyphens. In the past hyphens were treated as word separators while underscores weren’t.
CNET has a good summary of the news:
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.
Digg and Wikipedia are probably the largest sites that uses underscores and will see a huge increase in traffic. I’m not saying the increase in rankings for each page will be huge, far from it. However if each of Digg’s 2 million pages and Wikipedia’s 12 million pages ranks 1 place higher in the search results that’s going to equate to a load of traffic.
The last thing we need is Wikipedia getting more search engine traffic.