Every single domain name that is registered and hosted has lots of DNS records - some of them are set up automatically when you host a domain, others can be created manually if necessary. For example, the A record of a domain address is its IP address i.e. this record shows where the site is situated; the MX records show where the e-mails are managed, while using an SRV record you can use a domain for unconventional purposes, for instance a Voice-over-IP service. The ability to create and modify specific records enables you to have different services with different companies if, for instance, your present host provides dependable web hosting, but has problems with the email service, or you simply prefer to get a certain service from a specific company. Though you will be able to set up and edit these records freely and with no limits as you own a given domain name, a lot of companies charge extra to give you this option.