Youtube has come to define the era of online video, so lets take a look at their most popular videos of all time. We first did this list in august 2007, at which point evolution of dance by comedian judson laipply was number 1 with nearly 56 million views. The next update was september 2008, when avril lavignes girlfriend pop music video was number 1 with 103 million page views (although commenters argued that it may have gamed the system). In january 2010, charlie bit my finger - again ! Was number 1, with 148 million views. Our latest update shows that justin bieber is the first to break the 600 million views mark, after knocking lady gaga off the top spot this august 2010.