It is now visible on VIP Hotel Benefits when you log onto your account and updated in General HH terms and conditions, and here:
http://hhonors1.hilton.com/en_US/hh/about/diamond.do
Hilton® Hotels & Resorts
As a Diamond member, you receive the following benefits:
Upgrades to Preferred Rooms
Diamond HHonors guests will receive upgrades to preferred rooms, based on availability for the entire stay at the time of check-in. Upgrades for Diamond HHonors guests may include the next-best available room from the room type booked. Upgrades may also be rooms with desirable views, corner rooms, rooms on high floors, rooms with special amenities, rooms on Executive Floors**, or suites, as identified by each property. Some exclusions based on rate and room type may apply. See Terms & Conditions for details.
Hilton HHonors® Bonus Points
Earn 1,000 Hilton HHonors® Bonus Points per stay
Continental Breakfast
You will receive complimentary Continental breakfast for you and up to one additional registered hotel guest each day of your stay.