Having total control of your domains is something really important and being able to access and edit the DNS records for every single one of them is one of the things you should look for when you search for a registration or a hosting provider. You might have heard about the so-called “name servers” that show where a domain address is hosted, but below them there's a whole group of records, for example the A record, which is the IP address of the server hosting the site, and the MX records, which show the server that deals with the emails for a certain domain address. These records are used if you'd like to have your web site with one service provider and the emails with another, as an illustration. You can also use a domain for a non-website service or direct the traffic to it by using special records. A lot of companies ask for an extra payment to give access to edit certain DNS records besides the name servers.