In short: Hyphens are more search-engine friendly. If you want to receive top spots on Google, then a website URL of health-food-choices.com (for example) would be more efficient than healthfoodchoices.com.
A common question about SEO is this: “Are hyphens useful in your URL?” There are a few different views on this, but there is generally a consensus that hyphens are a good choice if you want high page rankings. Hyphens are used to separate keywords so that search engines can detect them. If you have a good, keyword rich URL and you want no confusion from search engines, then hyphens are good.
Example: business-exchange.com is more readable by webcrawlers than businessexchange.com. There could be some confusion with the latter domain name, but the former is very clear.
Hyphens are also good in subdomains. For example, a test conducted by webrankinfo.com showed this:
The following URL: wagatukepo-sitynozfau-mazidipole_vukertalet.php contains 4 keywords separated by hyphens or underscores. Before we started our test we did search Google for each of these keywords: wagatukepo, sitynozfau, mazidipole and vukertalet and there were no Google results. Few days later once Google indexed our new URL we did the same search for each of these keywords.
Results:
- wagatukepo: 1 Google result
-
sitynozfau: 1 Google result
-
mazidipole: No Google result
-
vukertalet: No Google result
-
mazidipole_vukertalet: 1 Google result
Conclusion: Google sees hyphens as dividers in URLs and ignores underscores
