"Gangnam Style" became the most watched YouTube video of all time, overtaking Justin Bieber
The rap -- named after a neighborhood of Seoul -- spawned countless parodies
Advertisers, campaigners and sometimes hapless individuals' videos have also gone viral
It is a guilty pleasure of anyone supposed to be working, and a time-waster that has kept millions of us up far too late at night.
Viral videos – from pop videos to advertising, parodies to accidental hits – have been entertaining, and occasionally informing, us like never before in 2012.
Here is CNN’s selection of some of the top viral videos this year.
Most watched viral video of all time: Psy: ‘Gangnam Style’
YouTube views at time of writing: 826 million
What’s the big deal: 2012 has undoubtedly been the year of “Gangnam Style.” This video by South Korean rapper Psy became the most-watched YouTube video of all time in November when it surpassed teenage pop star Justin Bieber’s 804 million views for “Baby.”
The rap is named after the pricey Seoul district of Gangnam and features 34-year-old PSY dressed in tuxedo and sunglasses dancing his much-copied galloping-style “horse dance.”
Best Gangnam parody: Mitt Romney Style
YouTube views at time of writing: 23.8 million
What’s the big deal: “Gangnam Style” has been copied and parodied so many times that we felt the tributes were worth a category in their own right.
Our favorite is “Mitt Romney Style,” by New York-based CollegeHumor.com, making fun of the Republican governor and failed presidential candidate’s wealth and swagger.
Best advertisement: A Dramatic Surprise on a Quiet Square
YouTube views at time of writing: 38.8 million
What’s the big deal: In this advertisement for the launch of the television channel TNT in Belgium, the company placed a big red button in the main square of a small Belgian town with a sign saying “Push to add drama.”
The ensuing chain of events – and the crowds’ reaction – when a passing cyclist presses the button, makes compelling viewing. CNN and TNT are both Time Warner companies.
Most-watched documentary: KONY 2012
YouTube views at time of writing: 94 million
What’s the big deal: Rarely has a campaign video gained such a reaction. This video by the San Diego-based campaign group Invisible Children about the African warlord Joseph Kony gained 74 million views within a week of its release in March.
Kony has operated in central Africa for two decades and is wanted for crimes against humanity by the International Criminal Court.
However the controversial video was dismissed by some critics as inaccurate, oversimplified and distracting from more effective charity work, and others questioned the group’s motives and transparency.
Best marriage proposal: Isaac’s Live Lip-Dub Proposal
YouTube views at time of writing: 16.3 million views
What’s the big deal: This makes a change from the schmaltz you might expect from a public marriage proposal, as actor Isaac Lamb organized this intricately choreographed live performance with 60 friends miming to the Bruno Mars song “Marry You.”
As Lamb wrote in the YouTube blurb: “I told my girlfriend to meet me at my parent’s house for dinner.
“When she arrived I had stationed my brother to sit her in the back of an open Honda CRV and give her some headphones. He ‘wanted to play her a song’ … What she got instead was the world’s first Live Lip-Dub Proposal.”
Best mis-hap: Catch the Ice Dude
YouTube views at time of writing: 21.3 million
What’s the big deal: This German man jumps dramatically into a frozen pool, not realizing quite how frozen solid it is. The result: Ouch!
The hysterical laughter from his friends and 21.3 YouTube viewings are Schadenfreude in action.
Best radio phone-in: Please Move the Deer Crossing
YouTube views at time of writing: 10.1 million
What’s the big deal: A woman who has become known as Donna the Deer Lady calls a local radio station in Fargo, North Dakota, complaining that deer crossings are encouraging deer to cross busy roads.
“Why are we encouraging deer to cross at the interstate?” she asks.
The presenter makes a brief attempt to explain that deer crossing signs are to warn motorists of areas with large deer population, rather than for the benefit of the deer, before giving up and agreeing to publicize her concerns.
Best public service broadcast: Dumb Ways to Die
YouTube views at time of writing: 25.3 million
What’s the big deal: This was created by the Melbourne Metro as a reminder that getting hit by a train is the dumbest way to die.
Other dumb ways to die suggested in the song and animated video include taking your helmet off in outer space, selling both kidneys on the internet and dressing up as a moose during hunting season.
Best corporate comebac: Bodyform Responds: The Truth
YouTube views at time of writing: 3.4 million
What’s the big deal: This video came after a man called Richard Neill posted an amusing rant on the Facebook page of sanitary towel manufacturer Bodyform complaining that their advertisements showing happy women taking part in extreme sports during their periods were misleading.
The company responded with a mock contrite apology video, supposedly from its managing director (although actually an actress) that they had lied to him about periods.