Each domain that is registered and hosted has a great deal of DNS records - some of them are created automatically when you host a domain, others can be set up by hand if required. As an example, the A record of a domain is its IP address i.e. this record reveals where the website is situated; the MX records reveal where the emails are managed, while through an SRV record you can use a domain for unconventional purposes, including a Voice-over-IP service. The ability to create and modify particular records enables you to have different services with different providers if, for illustration, your present host provides good web hosting, but has difficulties with the e-mail service, or you simply prefer to get a certain service from a specific company. Though you will be able to set up and modify these records freely and without any limits as you own a given domain name, a lot of companies charge extra to give you this option.