There have been the questions of "what exactly constitutes a viral video? How many views does it need to be considered 'viral'? How quickly does it have to rise in viewership?" There isn't exactly a set rule for how many "views" constitute a video "going viral". In a recent blog post, YouTube weblebrity
Kevin Nalty, aka Nalts, asks the question “How many views do you need to be viral?” In 2011 he said, “A few years ago, a video could be considered “viral” if it hit a million views.” But Nalts updated that definition. He said, “A video, I submit, is “viral” if it gets more than 5 million views in a 3-7 day period.”
[http://en.wikipedia.org/wiki/Viral_video#Number_of_views]