In an old
post (August 25, 2005) on his blog, Matt Cutts of Google wrote:
"I often get asked whether I’d recommend dashes or underscores for words in urls. For urls in Google, I would recommend using dashes."
More recently (
Wordcamp July 21st 2007), Cutts said that Google can read underscores, but that he still recommends using dashes:
"Now the interesting thing is that we used to treat underscores as if they were like word A Underscore word B We would glom that together. And we would index that as A underscore B If you searched for the word A we wouldn’t have returned your post.
"We are in the process of changing that. We might have already changed that.
"So dashes and underscores are almost exactly the same. But in engine world dashes are nice because if there is no space at all the search engine has to segment it.
"And Google can do that pretty well. We can break up words. But can every single search engine? Gigablast, Ask.com, Turbo10, you know, not every search engine will. Keep it simple and search engines will do it better by you."
So, hyphens still seem to be the way to go ...
Cheers, MJ