Christopher Wolf comments on the recent California case in which a UK council sought to unmask anonymous critics on Twitter:
… The ruling raises the question of whether foreign privacy law will be applied in the US. In this case, the ruling deprived someone of privacy (the anonymous online critic), but the outcome seeks to suggest that a US company may be subject to foreign privacy law, even if it conflicts with First Amendment principles.
In the EU, one element of privacy law is the right to know who is making anonymous criticisms. This has made it difficult for US companies operating in the EU to use anonymous whistleblower hotlines (deemed useful in corporate governance). In the US, of course, the right to criticize anonymously has a strong degree of First Amendment protection.
Read more on Hogan Lovells Chronicle of Data Protection.