The hyphen breaks up a longer domain name to reveal the major keywords that describe your website content or theme. This makes it easier for the visitor to understand and most importantly allows the search engine to detect your keyword for indexing right off the bat.

However, as search engine spiders get smarter and know what they want to qualify, the hyphen effect is less likely to influence any impact of the URLs on SE visibility. For URL branding purposes, it is also more viable to leave out dashes in between your URL’s name.