The 10 Most Watched Ads on YouTube in 2013

Going viral. It's become a kind of holy grail in advertising—manufactured by consumers, demanded by clients, parodied by agencies. But in a given year, only a handful of spots break through to become megahits—blowing past the 10 million views mark on YouTube (a useful guidepost for gauging supervirals) and engaging with blockbuster TV-size audiences.