According to Wikipedia, “the term viral video refers to video clip content which gains widespread popularity through the process of Internet sharing, typically through email or IM messages, blogs and other media sharing websites.”
Widespread popularity is probably an euphemism. Consider that the most popular video on YouTube, Evolution of Dance, has been seen more than 60 million times!
Now, if you haven’t been following the online video scene closely, you might want to check PC World’s article titled “Greatest Hits of Viral Videos.” They have listed 25 classics of the viral video phenomenon. Below you will find our favorite ones: