Complex sentence: In November 2009, the blog was one of the first websites to publish emails and documents from the Climatic Research Unit controversy, and thus played a key role, because of its high traffic numbers, in breaking the story to the global media.
Split into simpler sentences: In November 2009, the blog was one of the first websites to publish emails and documents from the Climatic Research Unit controversy. Because of its high traffic numbers, the blog played a key role in breaking the news of the controversy to the global media.