I appreciate the principled stand that Wikipedia is making against the potential threat against free speech constituted by the SOPA (H.R.3261) and PIPA (S. 968) legislation.
Today, January 18th, Wikipedia is officially on strike.
Naturally, I am completely opposed to the practice of pirating copyrighted material, which this legislation is ostensibly targeting. But the bills follow the chilling pattern of much recent legislation (e.g. Sarbanes-Oxley): presuming universal guilt and holding arbitrary power over every honest citizen.
Wikipedia has a good description of the purpose of their strike here, and Google has a petition you can sign here.