What makes the Internet unique is that it is the only communication infrastructure that is designed to make it easy for developers to apply it to new purposes. As a result, while the Internet does have organizations that are responsible for setting standards and managing some shared infrastructures, these play a very different role to organizations such as the International Telephone Union and International Postal Union.

Like the Internet itself, the organizations that support it have emerged piecemeal rather than from a planned design. As a result there is frequently a large measure of divergence between the apparent and the actual degree of influence each organization has.

For each organization it is useful to consider both the constituencies of interests it serves and which of those constituencies have an exit option and at what the cost of exercising that option would be.

For example, the IANA might appear to have the ability to constrain the growth of the Internet in a particular country by refusing to make new allocations of IP address blocks. In practice IANA has no ability to enforce such a policy. An IP address is after all merely a mechanism for identifying the destination of Internet packets to Internet routers. Operators of the routers will only reject packets for non-compliance with policies they agree on the need for.

This type of 'soft authority' is typical of the way Internet governance works in practice. Organizations can wield great influence if they continue to meet the expectations of the stakeholder organizations but neither the expectations, nor the stakeholders nor the consequences are fully clear. Making the situation clear is not necessarily advantageous.

Infrastructure Governance

IANA is the original source administrative support for the Internet. Formed by Jon Postel, the IANA is historically the source from which assignment of Internet protocol identifiers stems. In addition to DNS names, IP addresses and ASN numbers, this includes content types, encryption algorithms and hundreds of other identifiers that Internet protocols use internally.
After the formation of ICANN in 1998, responsibility for operating IANA passed to ICANN under an agreement that gives the IETF the ability to terminate the relationship with six months notice.
Internet Corporation for Assigned Names and Numbers (ICANN)
The best known of the Internet governance organizations, ICANN was formed to oversee operation of the Domain Name System (DNS). This has proved a highly lucrative activity allowing the 'not-for-profit' to generate revenues of over $200 million in 2014. This has in turn allowed ICANN to extend its influence by supporting other parts of the governance system.
Operation of the DNS is divided between the registries which perform the technical operation of the 'Top Level Domains' (TLDs) and the registrars which provide service to customers. In addition a panel of arbitrators appointed by ICANN resolve disputes brought under the Uniform Dispute Resolution Policy (UDRP).
Regional Internet Registries (RIRs)
The five RIRs are responsible for allocation of IP addresses and ASN numbers used for Routing at the Network and Link Layers. Each RIR periodically applies for and is granted new IPv6 address blocks from IANA. The five RIRs coordinate their activities through the Number Resource Organization, an organization started and maintained by the RIRs.
CA-Browser Forum
The CA-Browser forum was originally formed to develop 'extended validation' criteria for certificates for use with the Web PKI. It has since developed minimum validation criteria for all Web PKI certificates.

Standards

Internet

(Interaction complex)

The principal body that develops technical standards for Internet infrastructure, the Internet and Transport layers. The IETF is also responsible for some important Internet applications including the HTTP protocol and the protocols supporting the email system.
World Wide Web Consortium (W3C)
Responsible for development of standards that make up the Web as a platform other than HTTP.
Organization for the Advancement of Structured Information Standards (OASIS)
Develops specifications for applications, mostly based on XML.

Other

Is responsible for many of the physical and link layer specifications including Ethernet (802.3), WiFi (802.11) and BlueTooth (802.15).
International Telecommunication Union (ITU)
Was responsible for the

Special Interest

Formed to coordinate action against Intenet crime
Mail Anti-Abuse Working Group (MAAWG)
Formed to coordinate action against email spam and other forms of abuse.
Online Trust Alliance(OTA)
Formed to re-establish trust in the messaging system