Dashes Vs Underscores In URLs

Mar 15, 2007 web suggest edit

I used to think the choice of using dashes vs underscores to separate words in an URL was simply a matter of personal preference. Nothing more than a religious choice.

Personally, I preferred underscores because I felt dashes intruded upon the words while underscores stayed at the bottom out of the way. So much so I had originally made that the default URL scheme in Subtext for friendly URLs and was using that myself.

It wasn’t till recently that I learned this debate has already been resolved. Years ago.

I wouldn’t say resolved really. Just that, there appears to be a really good reason to choose dashes over underscores. Apparently, Google sees the dash as a word separator, while the underscore is perceived to be part of the word. Something to do with being able to search for C++ style constant variables SUCH_AS_THIS in the title of a post.

The question is, does this still apply today? Does iteven matter?

To be on the safe side, I’m falling in line for now. Or rather, in dash. What are your thoughts?

Found a typo or mistake in the post? suggest edit

Comments

21 responses

simoncox • March 15th, 2007
I am glad someone else is bringing up this debate again. For me it has not been resolved because the accepted way is for programming not for the common language usage of hyphens. Google got this wrong and have not put it right yet, or have they...
Rob Conery • March 15th, 2007
Underscores are terribly hard to see at times, and more than once (when a word is underlined or part of a hyperlink) I've misspelled the URL or just missed it altogether.
Dashes, em-dashes, hyphens: it's all pretty confusing idn't it? I mean what do you do when a post title has a dash in it? Remove it only to put it back :)?

For me it has not been resolved because the accepted way is for programming not for the common language usage of hyphens

Isn't that what we're talking about?
Steven Harman • March 15th, 2007
Good thing we made that totally configurable in Subtext. It took me all of 3 seconds to change the URL construction for my blog - and 2 of those seconds were spent navigating to my site's web.config file.
Also... when did you change Subtext to add the "author" class around the comment div for the Comments.ascx control?
James Chen • March 15th, 2007
Dashes bring better readability than underscores, especially when the URLs are displayed on pages with the underline style.
Jay Flowers • March 15th, 2007
There is more on the why here:
http://www.codinghorror.com...
Jeff Atwood • March 15th, 2007
That's right. It's all about regex. Try a \W (word character) match and see what happens.
This_is_one_word.
This-is-multiple-words.
I also agree with the earlier comments that underscore sucks for other reasons. It's less comprehensible.
Jayson Knight • March 15th, 2007
Hyphens all the way here...much more readable IMO.
Maurice Prather • March 15th, 2007
Who cares?
As a human, it doesn't really matter. Yes, there are some points about readability vs. typeability vs. recognizability. As long as I can recognize the url as a url, I'm good. I can always cut/paste, click on a link, etc.
As a search engine, this should absolutely not matter. If a search engine is relying on a url to give a page relevance (even if the contribution percentage is small), then I would say that relevance calculation is broken. Content matters, not the url.
Dave Frank • March 15th, 2007
If you surf around botw:
http://botw.org/top/Health/...
you'll see that we use underscores for spaces in the URL. Why? because it looks nicer than %20 which spaces tend to show up as, more often than not. If you had dashes for the spaces, and then had a word with a dash in it, the system could get confused.
You can see what happens with these category names:
Wolverine-Hoosier Athletic Conference
2gether - The Series
Northeast-10 Conference
Northern Illinois-Iowa Conference
Magazines and E-zines
Magazines and E-zines
Ramstein-Miesenbach
K-12
Have Gun - Will Travel
Rehburg-Loccum
Co-Ed
Scott • March 15th, 2007
Know why I hate 'em?
C & C++ folks overused them. Quick, how many underscores in this constant. Change your font, now how many? Argh!
___EVIL_LONG_CONSTANT__
Haacked • March 15th, 2007
The dash being easier to type is a GREAT consideration.
Originally, I used Wikicasing for my URLs. Now I'm trying out dashes. It's like the fashion style. I'm wearing what's en vogue.
Tomorrow I'll use another character. Maybe the "Y"!
Haacked • March 15th, 2007
> Also... when did you change Subtext to add the "author"
> class around the comment div for the Comments.ascx
> control?
Last night.
German Rumm • March 15th, 2007
I'm using dashes. Because of Google and because it's prettier.
Underscore is not even a character. Historically, it's a type-writer "hack" - to make it easy to underline words.
Computer keyboard was copied from type-writer, and that's why we have underscore and QWERTY layout.
Robb Allen • March 15th, 2007
You can have my underscores when you pry the bits from my cold, dead, L2 cache.
Honestly, I'm agnostic, although anything that irritates Google is good for me. Google is NOT the MCP (anyone else remember Tron?) and we should not force our coding standards to make Google's life easier. Google is supposed to adapt to us, not vice versa.
That being said, dashes are easier to read, for sure.
Ryan Smith • March 15th, 2007
It's funny that Atwood brings up the point that the regular expressions are easier to write in order to parse the URLs with dashes.
I had the exact opposite problem. I would run a regular expression on my friendly URLs to make sure that there were only valid alphanumeric characters. The dash would break this so I had to rewrite my regexp.
Not that this was difficult, but I never looked at from the other point of view.
Tom's Blog • April 23rd, 2007
Dashes Vs Underscores In URLs Dashes Vs Underscores In URLs .
David Huntley • June 4th, 2007
I'm i not correct in thinking that domains can not contain an underscore character if you want to have compatibility with IE and cookies? Surely that's reason enough to switch if you haven't.
Timothy (TRiG) • January 18th, 2009
It's true that underscores are not allowed in domain names, but they're perfectly valid in the rest of a url (just as question marks, ampersands, and solduses (soldi?) are).
That said, I think some domain name registries do allow underscores in domain names, which they really shouldn't. In fact, that's what I was looking for when I came here.
On this subject, I like the look of underscores, because they more clearly separate words, while hyphens bring words together. That's their function in language, and I like to differentiate. But hyphens are easier to type, so I'm undecided. So far, I've gone with hyphens. Camel case is evil.
TRiG.
Đồ gia dụng • January 10th, 2013
DDoo
Đồ gia dụng • January 10th, 2013
Thanks for sharing
numediaweb • March 1st, 2017
10 years later..

Here are a few points in favor of the dashes:
* Dashes are more familiar to the end user.
* Dashes are easier to write on a standard keyboard (no need to Shift).
* Dashes don't hide behind underlines.
* Dashes feel more native in the context of URLs as they are allowed in domain names.