ICANN

The Internet Corporation for Assigned Names and Numbers (ICANN, is a non-profit corporation, created on September 18, 1998, and incorporated on September 30, 1998 to oversee a number of Internet-related tasks previously performed directly on behalf of the U.S government by other organizations, notably the Internet Assigned Numbers Authority (IANA), which ICANN now operates.
ICANN is responsible for the coordination of the global Internet's systems of unique identifiers and, in particular, ensuring its stable and secure operation.This work includes coordination of the Internet Protocol address spaces  and assignment of address blocks to regional internet registries, for maintaining registries of Internet protocol identifiers, and for the management of the top-level domain name space which includes the operation of root nameservers.
Before the establishment of ICANN, the Government of the United States controlled the domain name system of the Internet. The original mandate for ICANN came from the United States government.

At present, ICANN is formally organized as a non-profit corporation "for charitable and public purposes" under the California Nonprofit Public Benefit Corporation Law. It is managed by a 16-member Board of Directors, which is composed of eight members selected by a Nominating Committee on which all the constituencies of ICANN are represented; six representatives of its Supporting Organizations, sub-groups that deal with specific sections of the policies under ICANN's purview; an At-Large seat filled by an At-Large Organization; and the President / CEO, appointed by the Board.
There are currently three Supporting Organizations. The Generic Names Supporting Organization (GNSO) deals with policy making on generic top-level domains (gTLDs). The Country Code Names Supporting Organization (ccNSO) deals with policy making on countrytop-level domains (ccTLDs). The Address Supporting Organization (ASO) deals with policy making on IP addresses.
ICANN also relies on some advisory committees to receive advice on the interests and needs of stakeholders that do not directly participate in the Supporting Organizations. These include the Governmental Advisory Committee (GAC), which is composed of representatives of a large number of national governments from all over the world; the At-Large Advisory Committee (ALAC), which is composed of representatives of organizations of individual Internet users from around the world; the Root Server System Advisory Committee, which provides advice on the operation of the DNS root server system; the Security and Stability Advisory Committee (SSAC), which is composed of Internet experts who study security issues pertaining to ICANN's mandate; and the Technical Liaison Group (TLG), which is composed of representatives of other international technical organizations that focus, at least in part, on the Internet.
One task that ICANN was asked to do was to address the issue of domain name ownership resolution forgeneric top-level domains. ICANN's attempt at such a policy was drafted in close cooperation with the World Intellectual Property Organization (WIPO) and the result has now become known as the Uniform Domain-Name Dispute-Resolution Policy (UDRP). This policy essentially attempts to provide a mechanism for rapid, cheap and reasonable resolution of domain name conflicts, avoiding the traditional court system for disputes by allowing cases to be brought to one of a set of bodies that arbitrate domain name disputes. According to ICANN policy, a domain registrant must agree to be bound by the UDRP — they cannot get a domain name without agreeing to this.