Dash vs Underline
 

I know this has been talked about in another post but I can't find it. For sites with more than one word, which is better to seperater the words, a dash - or an underline _?

i heard that google reads a dash (-) like a space, so it's better to use a dash.

TRUE!
|thumb

Well crap, the last 10 sites I built I used underlines |cry| |banghead|

Underline is not intended to separate words

Underscores work better when you're sending URL's through email. Sometimes a url with dashes gets cut off:

> domain.com/this-url-with-dashes
> no-longer-works/index.html

Also, consider this:

domain.com/series-of-words-using-dashes-reads-choppy/index.html

vs.

domain.com/series_of_words_using_underscore_reads_easier/index.html

When it comes to SEO, url structure seems to have such a small impact compared to so many other things I wouldn't worry about it.

However, if someone uses the url string as the anchor text, dashes are more SEO friendly:

domain.com/each-word-is-read-seperately/index.html
domain.com/all_one_word/index.html

I used to think this a good idea, but I send a lot of download URLs for eBooks I sell, and since URLs in emails get underlined an underscore disappears in the line. This is fine if the recipient just click on it, but too many copy (by retyping not 'copy and paste') the URL, and put a space instead of _ . They then email me and tell me that the download URL does not work and I have to waste time explaining why.

Google engineers are geeks (surprise, surprise). They care about searches like "HTTP_EQUIV", "_SERVER", "DOCUMENT_ROOT."

but, they are python geeks, and wouldn't search for _SERVER. :)

Come on, someone over there's gotta like PHP... :D

Lets put this to rest - here's exactly how Google looks at dashs vs underscores - written by their rep:

http://www.mattcutts.com/blog/dashes-vs-underscores/

Note that they treat word1_word2 differently than word1-word2

in order for a search to show for the first example the searcher would have to type in the whole phrase wheras the second example Google treats as two separate words