Haiti earthquake, Gulf oil spill and Britain's Prince William's engagement -- these are among the top 10 most powerful topics which dominated the 25 billion tweets this year, according to Twitter.

In the micro-blogging site's list of the top 10 trends of 2010, 'TODAY' show anchor Ann Curry's 50-character message imploring the Air Force to allow physicians to land in Haiti to administer aid to the injured and dying came in No 1.