It is very professional; not only is a creatively sliced, diced and spliced together, but it is almost an entirely new track in itself and quite listenable.

It is a great reminder of what has been the biggest impact hits of the year, and just how important video has become to music - they are intertwined with so much media now consumed on youtube and the like, it is vital that your video presence is as great as your audio one. In the days of auto-tune, and the general acceptance of this as an "artform" you no longer even need to be a great singer to be a certified star!

This mashup was made by DJ Earworm; this dude is a professional, or has way too much time on his hands - his youtube channel has got a bunch of other youtube mashups that he has also created.
He is also available for parties.....

The track features video snippets from top artists this year such as Lady Gaga, Katy Perry, and Ke$ha.

The full list of artists and songs in the mashup is:

Ke$ha - Tik Tok
Lady Antebellum - Need You Now
Train - Hey, Soul Sister
Katy Perry Featuring Snoop Dogg - California Gurls
Usher Featuring will.i.am - OMG
B.O.B. Featuring Hayley Williams - Airplanes
Eminem Featuring Rihanna - Love the Way You Lie
Lady Gaga - Bad Romance
Taio Cruz - Dynamite
Taio Cruz Featuring Ludacris - Break Your Heart
B.O.B. Featuring Bruno Mars - Nothin' On You
Enrique Iglesias Featuring Pitbull - I Like It
Young Money Featuring Lloyd - Bedrock
Jason Derulo - In My Head
Rihanna - Rude Boy
Lady Gaga Featuring Beyonce - Telephone
Katy Perry - Teenage Dream
Bruno Mars - Just the Way You Are
Mike Posner - Cooler Than Me
The Black Eyed Peas - Imma Be
Jay-Z + Alicia Keys - Empire State of Mind
Usher Featuring Pitbull - DJ Got Us Fallin' In Love
Travie McCoy Featuring Bruno Mars - Billionaire
Eminem - Not Afraid
Iyaz - Replay