Cahill, a high school sophomore with a rare disorder, had been posting videos of himself singing and lip-syncing pop songs since last October with some notice. But it wasn't until his version of "Teenage Dream" -- which has been viewed over 24 million times, was acknowledged by Katy Perry herself, and became one of our most heavily shared videos -- that Cahill began to take off and started averaging millions of views per week.
Between last October and this August, Cahill's videos were viewed 2.6 million times, which may seem like a lot. But compare that to the 125.7 million views he's drawn since. In addition to creating several popular new lip-syncs, Cahill has also done cameo videos with 50 Cent and WGN's morning show team.
As you can see in this chart showing views from this Fall, that 50 Cent cameo created a big spike for Cahill in November (mouse over the dots for more info):
More of Cahill's most popular videos:
• See also - Top 10 Most Shared Videos of 2010