There aren't a lot of lists of "viral videos" or "hit videos" out there. Which I found very surprising. So, I went to the source ... YouTube. You can find the sorted list of their top most viewed videos at YouTube. Of interest, I think you find a different list if you are logged in (i.e. more "adult oriented" in nature) than if you are not logged in (i.e. more PG).
Also, you can filter their list by "when" (today, this week, this month, this year, or all time), and by video or channel.
I'll admit I've been enjoying following the Sons of Maxwell song and crusade against United Airlines pathetically bad customer service. This is a story - and one would like to hope a big exception, but somehow I doubt it - about an experience gone terribly awry, and the great ability of a consumer to create an enormous amount of buzz in their own defense, using the power of the internet to communicate and engage.
Both of those happenings led me to start thinking about viral videos, how they work, and what they are. Maybe this song and video are "anti-buzz" against United Airlines. In any event, it is amusing and ever so telling about their overall way of doing business. It also shows the power of a consumer with a good story in the internet age.
By the way - the views on that video are on fire. They have had more than 2.7 million views in less than a week. The majority of the comments on the vlog clearly feel their pain, and express anger and frustration at United and other airlines.