The Center For Internet And Society, Stanford Law School — “The Senate is still pressing ahead with PIPA’s most dangerous provisions intact, including those that would force internet service providers to block access to entire sites through DNS blocking and other means that threaten both the universality and the security of the internet itself,” warns executive director, Fair Use Project and Lecturer in Law, Anthony Falzone.
If you want take your site down, the CIS has links to some tools from CloudFare and Webmonkey you may find helpful.