So a considerable number of countries, including the United States, have refused to sign the new International Telecommunication Regulations ("ITRs"), which together form a new version of the international treaty on telecommunications. More have indicated they will need further instructions from their national capitals before deciding whether or not to sign.
In the end, the new ITRs and the documents circulated with them contain a number of provisions that seem to have raised enough concerns for the United States, Canada, the UK, New Zealand, Australia, Sweden, Costa Rica, and Denmark, at least, to refuse to sign them. These provisions include:
A paragraph in the Preamble stating the Member States have the right to access international telecommunications services;
An article (5A) on the "Security and robustness of networks";
An Article (5B) on "Unsolicited bulk electronic communications";
A Resolution (3) entitled "To foster an enabling environment for the greater growth of the Internet" that recommends the ITU "play an active role in the development of broadband and the multistakeholder model of the Internet. (Note that the resolutions aren't formally parts of the ITRs, but they accompany them)
These map to a large extent, though not exactly, to specific issues that the United States mentioned in its press conference yesterday as being "critical" to its position:
Internet governance can only be handled by multi-stakeholder organizations;
Spam, a form of unsolicited bulk communication, is nonetheless also a form of content, and regulating it at the international level could lead to regulation of other forms of content and speech;
The ITRs aren't the right place to address network security issues, since they can easily have bad effects on communications without actually improving security;
The Internet Resolution was a direct extension of the ITU's scope to the Internet, despite early assurances that this was not on the table.
Your take on the effects of this will depend upon how you weight and then balance the following value judgments:
The ITU is not the best place to cover a number of Internet issues—and particularly ill-suited to address issues of Internet content.
The new ITRs actually do cover a number of new issues (spam, security, and the Internet) that don't belong in the ITU
Many countries frequently use "security" and "spam control" as pretexts for justifying censorship and surveillance;
The ITU serves a purpose in coordinating international agreements on telecommunications; it would be a loss if member countries stopped using it for that purpose.
The extent to which you believe each of these things will dictate how happy you are with the current state of affairs, which has ITRs with language referring to certain types of unsolicited bulk communications (but not email or spam by name), an article on network security, and a resolution on Internet governance that is actually somewhat ambiguous on how much it wants governments to have a role in it (it supports multistakeholder processes, but keeps emphasizing the role of governments within them).
So the effects of walking away from the new ITRs for individual countries depend on how the treaty would or would not have been implemented by various countries; its effects on their citizens would be one concern; another would be how different implementations might affect relations and communications between different countries. Another question of effect is on the influence and significance of the ITU. If a large number of Internet-heavy, powerful, and/or populous countries are willing to walk away from the organization, how much will the world pay attention to it in the future.
Regardless, the full effects are something that will emerge over time. The lack of agreement doesn't lead to some catastrophe; we will continue to maintain telephone and Internet links with the countries that did and didn't sign the ITRs. The new ITRs themselves won't even take effect until the beginning of 2015, and even after that, much will continue as normal. Still, the new ITRs may increase the perceived legitimacy of inter-governmental efforts to control Internet governance and content, and may decrease our ability to handle Internet governance issues through traditional multi-stakeholder forums. In other words, the significance is more political than legal, and its effects will be most felt not inside many countries, but in the discussions between them.