Using dashes, rather than underscores for SEO’s reason

Google indexed numbers and some punctuation . With underscores, Google�s treat it as unusual way I think. For example, languages have web_hosting, which may be different than web. So if you have a url like web_hosting, Google will only return that page if the user searches for web_hosting (which is rare to happen). But If you have a url like web-hosting, that page can be returned for the searches web, hosting, and even �web hosting?.

That�s why we should use dashes, rather than underscores. Generally Google doesn�t algorithmically penalize for dashes in the url. This may be true only for Google, not other search engines in the internet.