A New HTTP Status Code for Legally-restricted Resources

3.  451 Unavailable For Legal Reasons

   This status code indicates that the server is subject to legal
   restrictions which prevent it servicing the request.

   Since such restrictions typically apply to all operators in a legal
   jurisdiction, the server in question may or may not be an origin
   server.  The restrictions typically most directly affect the
   operations of ISPs and search engines.

   Responses using this status code SHOULD include an explanation, in
   the response body, of the details of the legal restriction; which
   legal authority is imposing it, and what class of resources it
   applies to.  For example:

http://tools.ietf.org/html/draft-tbray-http-legally-restricted-status-00