Wired has a great article on the current state of the US government's use of both traditional sites (there are 24,000!) and social media and how President Obama's administration will affect the future use by the Feds.
There are things they can't do by law:
"No We Can't
Barack Obama wants to transform the way the White House connects with the public. But there are plenty of obstacles standing in his way.
A Ban on Endorsements
Since the government cannot endorse commercial private organizations, some federal Web pages cannot link externally.
Restrictions on Revisions
The Presidential Records Act requires the preservation of all written communications, which limits Web page modification.
Survey Rules
A detailed approval process is required to "survey" more than 10 people. Soliciting user input may fall into this category.
Access for the Disabled
The Rehabilitation Act requires that all government Web content be made reasonably accessible to those with disabilities.
The US Constitution
The First Amendment's prohibitions on restricting speech may limit the federal government's ability to filter user comments.
Purchasing Rules
Federal agencies must follow contracting rules when they make commercial software purchases costing more than a certain amount.
License Agreements
The Feds can't draw on content from sites like YouTube that require terms-of-service agreements based on state laws."
From Wired.com. Highly recommended.
