There has always been confusion in the SEO industry surrounding hyphens/dashes in domain names, and how/if they effect search rankings. And what about underscores in domain names, how does Google handle these?
Google sees hyphens as ‘spaces’ so if you were to have the domain love-dashes-forever.com Google will read this as ‘love dashes forever.com’ – this would technically be the correct way to write a domain with multiple words. This means having hyphens in your domain name will not affect your SEO in a negative way however, it does add some extra characters to the domain name, which isn’t good in terms of usability since a longer domain is easily forgotten.
An example of a good hyphenated domain name would be:
Whereas a bad example of a hyphenated domain would be:
A general rule of thumb would be to use no more than two hyphens in a domain name. There are lots of popular websites online that use hyphens and rank well within the search engines, for example: heathrow-airport-guide.co.uk – it’s not the shortest domain but it ranks well in the search engines and I imagine gets a lot of traffic.
Using hyphens in domain names is essential if you are connecting a word that is not commonly used, for example if you are using a unique brand term or a made up word like ‘dawgar’. If you connect this word to a keyword, for example ‘dawgar SEO’ or ‘dawgarseo.com’ Google cannot split the two since it doesn’t recognise the word dawgar, so Google will see it as just one long made up word; however, if you split it with a hyphen (a space) Google will give weight to the keyword SEO.
To sum up, using hypens / dashes in domain names is fine, as long as the domain doesn’t look spammy and isn’t too long.
What about underscores in domain names?
Underscores unlike hyphens are NOT counted as spaces; instead they are counted for nothing other than an underscore, for example:
When using hyphens ‘Hyphen-Domain’ is seen and understood by the search engines as ‘Hyphen Domain’. When using underscores ‘Under_Domain’ is seen and understood as just that ‘Under_Domain’.
You shouldn’t really use Underscores in domain names – stick to hyphens, they do not effect SEO and in some cases can actually have a positive effect on your rankings.
Just in case you’re still in doubt, Matt Cutts clears it up here: