You are so proud to share your discoveries but no one is glad enough to explain WHY all is black & white!
=> It's because it's a national mourning day in china due to the deads in the floods
logo with chinese sign
There was no good references yet when the first forum posts were posted. Personally I gathered information via local news (using AFP as source).
This happened in May 2008 too:
'Chinese websites turn sombre as nation mourns earthquake victims'
My source in this month:
Examples are from search engines etc, there is China Daily's page: