The Top 10 YouTube videos:
1. "PSY — Gangnam Style": This crazy South Korean pop music video surprised the world by becoming the most viewed video of all time in just six months.
2. "Somebody That I Used to Know — Walk Off the Earth (Gotye — cover)": The most-viewed cover song of 2012, otherwise known as "5 people, 1 guitar," attracted 140 million views this year.
3. "KONY 2012": For one week, this was the most-shared video in the world. The cause-based video garnered the most views ever for a YouTube video in a single day (31 million).
4. "Call Me Maybe" by Carly Rae Jepsen — Feat. Justin Bieber, Selena, Ashley Tisdale & More!": This video covering the song of the summer kicked off a trend of lip sync videos that spanned from the Harvard baseball team to celebrities to Olympians.
5. "Barack Obama vs Mitt Romney. Epic Rap Battles Of History": This episode, featuring well-known Obama impersonator Alphacat, is from YouTube's "Epic Rap Battles" which drew over 250 million views this year. It also points to a larger 2012 trend: Videos of Obama and Romney were viewed well over 2 billion times.
6. "A Dramatic Surprise On a Quiet Square": What happens when you place a mysterious sign in the middle of a Flemish square? The world wanted to know as this video brought in 25 million views in the first week it was posted, with more than 1 million views in each of 10 countries.
7. "Why You Asking All Them Questions": Comedian Emmanuel Hudson's popularity exploded this year, especially in the southern U.S. with almost half of this video's 39 million views coming from mobile devices.
8. "Lindsey Stirling": Lindsey's trademark dubstep violin styles created a lot of buzz this year, especially in the U.S., Germany and Poland. This video has over 500,000 likes and 100,000 comments.
9. "Facebook Parenting: For the Troubled Teen": A father's reaction to his daughter's Facebook post set off a storm of controversy, discussion and response videos, with 11 million views in just one day.
10. "Felix Baumgartner's supersonic freefall from 128k' — Mission Highlights": This live stream of Felix Baumgartner's free-fall from 128,000 feet shattered previous live stream records with 8 million concurrent views.