Hyphen or Underscore?

[MattM]

I don't know if this even matters or not, but, when creating page file names, is it better SEO when seperating words to use a hyphen or underscore?

Example: file-name.php or file_name.php

[Chris]

hyphen, because Google (for some unknown reason) does not treat an underscore as a space (unless they recently fixed this).

[chromate]

I think hyphen's better. But I'm not actually sure if it matters these days.

[Yoda]

Originally posted by Chris
hyphen, because Google (for some unknown reason) does not treat an underscore as a space (unless they recently fixed this).
Is it different with folders, or files that appear the same as folders (through mod_rewrite)? I ask because this site seems to use underscores.

[ozgression]

No, same rule apllies to folders (as far as I know).

[Chris]

Everyone other than Google uses underscores as spaces so for a long time thats what I used, I never bothered to test it with Google because it was standard. In applications when you cannot use spaces an underscore is the standard substitute.

However I then tested Google one time and found out that I shouldn't have assumed that they'd be like everyone else. Since that time I've used hyphens, but much of this site was made before I realized.