Every registered domain name has no less than 2 Name Server records that show where it is hosted i.e. by using these records you point your Internet domain to the servers of a specific hosting company. This way, you have both your site and your e-mails handled by the very same service provider. On the lower level of the Domain Name System (DNS), however, there are a number of other records, for example A and MX. The former shows which server handles the website for a given domain address and is always an IP address (188.8.131.52), while the latter shows which server deals with the emails and is always an alphanumeric string (mx1.domain.com). As an illustration, whenever you type a domain address in your web browser, your request is directed through the global DNS system to the provider whose NS records the domain name uses and from there you will be forwarded to the servers of another company if you have set an IP address of the latter as an A record for your domain. Having independent records for the site and the e-mails means that you may have your website and your emails with two different providers if you would like.