Dashes are better than Underscores ...

... between keywords in file names.

[skyhawk133]

In a guest post by Vanessa Fox on Matt Cutt's blog, Vanessa points out dashes are much better than underscores. Matt later bolds this line in the blog entry for emphasis.

I had not thought about this, but apparently blue_widgets.html is considered 1 word, where as blue-widgets.html is considered 2 words. So for multi-word titles used as static HTML names, it looks like using a hyphen is far better than using an underscore. A brief look at the SERPS does confirm this.

[kaled]

It's a fact that underscore is not a letter. Essentially, it is used by programmers, etc., instead of space in identifier names.

Search engines should treat underscores as :-
spaces in documents
binders in searches (e.g. "my world" == my_world)

However, so far as I am aware, search engine designers haven't figured this out yet.

Kaled.

[g1smd]

As was previously explained by several people, underscores are used in compter programming, so those people want to make searches that include an underscore and look only for exact matches: like HTTP_HOST for example; and not including any pages that merely mention the word HTTP and the word HOSTS.

Did I mention that dots work the same way as hyphens, and look nicer too?

[Hissingsid]

Hi,

I'd just like to apologise for talking out of my ar-$e earlier.

If you try a search for each of these you get different results.

stylecodes
style-codes
style_codes
style.codes

Sid

[Halfdeck]

If you try a search for each of these you get different results.

stylecodes
style-codes
style_codes
style.codes

Easy test:

Build a few pages, e.g. redwidget.com/redwidget.html, redwidget.com/red_widget.html, red-widget.com/blue.html. Don't use the words "red" or "widget" in the page copy. Use some random text to link to those urls.

Wait till the three pages are indexed.

Now, run "site:redwidget.com red widget" in Google. It will return 1 match: red-widget.com/blue.html.

[g1smd]

Hmm. I made a post over at Matt Cutts blog about dots in URLs. It was in amongst a discussion about hyphens in URLs and I now see that the comment was deleted.

Hoever, that was not before other people had seen it, I guess, as there are now several (unanswered) questions about dots in URLs that have been made in later postings.

Hopefully they will find this thread...

[texasville]

I am absolutely positive that I saw a Google Guy post somewhere (could have sworn it was here) in the past year that underscores are NOT treated as spacers by the bots. He said green_widgets would be read as greenwidgets.
I remember it so well because that is when I got the stupid idea to make pages as:
green widgets.htm

and then I saw that since I was on a ms server it was automatically changed to 20% or whatever in between the words. Then I found that unix servers would not read that at all. Gad my learning curve was painful.

<edit to add>

I just googled the matt cutts underscores and dashes thing. It was his blog. Not GG.

[g1smd]

Yes. Avoid spaces and underscores in URLs.

Always use hyphens or dots between words.