As part of its new draft Compendium of U.S. Copyright Office Practices, Third Edition, we have guidance on registration for websites.  The draft of the full compendium is over 1200 pages and covers publication, recordation, notice, deposits, along with other topics.  Members of the public may make comments anytime before (or after) the Third Edition goes into effect on December 15, 2014. For more see  http://copyright.gov/comp3/