Google has attempted to encapsulate the year with the video above, which covers some of the most searched subjects of 2012, scored to "All I Want" by Kodaline and produced by Whirled.*
I'm with the YouTube commenter who thinks "Dumb Ways to Die" didn't have that much effect on the 2012 zeitgeist. Still, pretty good video.
* This sentence has been updated with additional information about the video.