This is a research project, not an actual government site. However, it looks interesting enough to be listed here.
From the website:
Regulation Room is designed and operated by the Cornell e-Rulemaking Initiative (CeRI) and hosted by the Legal Information Institute (LII). The site is a pilot project that provides an online environment for people and groups to learn about, discuss, and react to selected rules(regulations) proposed by federal agencies. It expands the types of public input available to agencies in the rulemaking process, while serving as a teaching and research platform.
CeRI is a multidisciplinary group of faculty and students, based at Cornell University. We work with federal agencies to discover the best ways to use Web 2.0 and other technologies to improve public understanding of, and participation in, rulemaking. LII, based at Cornell Law School, has been providing legal information at no charge to the public since 1992, and is the most linked-to web resource in the field of law.
CeRI cooperates with various federal agencies to select and present the proposed rules that are available in Regulation Room. However, this is not a federal government site. Discussions on Regulation Room are moderated by CeRI students and faculty or other nongovernmental researchers collaborating with CeRI. The federal agencies whose rules are offered here collaborate in this research, in order to learn about the most effective Web 2.0 strategies for increasing public understanding and participation during rulemaking, but all content and operation are the sole responsibility of CeRI.
The site is built on Wordpress.