This is great communication. Shocking. Informational. Google has done such a smart job of setting up a theme and variations
by the consistent use of the spare, stark white home page...and then playing variations on it...usually through the logos for holidays.
The Google landing page could work better as it's a bit too Googlecentric for my taste.
But the Earth Hour page is terrific. Love the ability to email friends to alert them, the clock and the ability to watch major monuments/sites go dark in Sydney last year.