Every domain name which 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 created manually if needed. For instance, 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 stored, while through an SRV record you can use a domain address for unconventional purposes, such as a Voice-over-IP service. The ability to set up and modify certain records enables you to have different services with different companies if, for example, your present host provides good web hosting, but has problems with the email service, or you simply prefer to get a particular service from a particular company. Even though you should be able to create and modify these records freely and with no limits as you own a given domain, many companies charge extra to give you this option.