[airpoint]

Mostly incorrect. The First Amendment limits the US government, not Ofcom or UK courts. UK law can regulate services with “links to the UK” even if the provider is abroad, and Ofcom’s enforcement does not itself abridge anyone’s US constitutional rights.

[Zak]

It's sovereignty that limits the UK courts from enforcing a fine against an organization without a physical, legal, or financial presence in the UK. They could ask US courts to enforce a UK judgment, but the First Amendment does bind US courts.

[EarlKing]

The first amendment is a natural right, not a civil right, but at any rate the matter of personal jurisdiction is what is at issue, which most definitely does regulate who can and cannot assert authority over a man (fictive or otherwise). Ofcom's attempt to enforce their law over corporations and people who do not in fact have "links to the UK" as defined under US law is the entirety of the issue. They are overstepping their jurisdiction and infringing upon the sovereignty of the United States.