Dashes v Underscores in webpage names

We recently has an internal discussion about dashes verses underscores in website page names and thought it was worth clarifying this point.

You should use dashes rather than underscores in your webpage names because Google will parse a dash as a space, thus separating words you want separate. But an underscore remains an underscore, which means people would have to search for the words with an underscore between them.

Example: Let’s say you’re selling icons. And you have some Vista and XP icons for sale. You’d like to do everything you can for Google to place your website highly for the phrase “Vista icons”. So you name one of your webpages vistaicons.html. Bad idea. People don’t search for “vistaicons”, they search for “vista icons” (note the space).

OK, fine. So you name your webpage vista_icons.html. Still a bad idea, because Google doesn’t translate the underscore to a space. It thinks when you have an underscore, you mean an underscore. Which means people would have to be searching for “vista_icons” for this one to work.

Why do underscores stay as underscores, instead of being translated as a space (which is what you wanted, right)? Because Google was written by computer nerds, and in the computer nerd world, underscores are important characters. If Mr. Nerd is searching for a technical term that has an underscore in it, he will not appreciate Google turning the underscore into a space. To a hardcore computer nerd (and we know Google has a few of those on staff), an underscore is an underscore, thank you very much. It is not a space. Kinda like the letter “a” is the letter “a”, not the letter “b”.

So if you want Google (and presumably, other search engines) to parse your webpage name into separate words, and hopefully give you a little SEO boost for those words (assuming they exist in your webpage as well), then use a dash between the words. Thus, for our example, the best webpage name would be vista-icons.html.