A registrar is an organization that has been accredited by ICANN to register top-level domains (TLDs) — that is, domain names ending in standard extensions such as .com, .org, or .info. Your domain name registrar is responsible for maintaining your domain registration records, managing your domain renewals, and other administrative details. Yahoo!'s domain registration partner, Melbourne IT, is the registrar for all new domains registered through Yahoo!
When you register a domain name, your registrar submits technical information surrounding your domain name to a central registry; the information stored in this registry allows other computers on the Internet to find your domain, making it possible to view your web site or send you email.
You'll need to communicate with your registrar if you want to renew your domain and whenever you want to make changes to your domain name information, such as your contact address, name servers, or advanced DNS records. Your registrar is also required to keep a record of your personal contact information. Learn more.