A few hours after EFF and the ACLU of Northern California filed a class action lawsuit challenging California's recently enacted Proposition 35, the court issued a temporary restraining order, blocking implementation of the initiative due to the existence of "serious questions" about whether it violated the First Amendment. Proposition 35 is ostensibly about increasing punishment for human traffickers, but would also require all registered sex offenders in California to turn over a list of all their Internet identifiers and service providers to law enforcement.
https://www.eff.org/deeplinks/2012/11/court-blocks-proposition-35s-restriction-anonymous-speech