This is pretty much a great way to waste your time online as you would have to watch two videos and decide which one you want to vote for.
This has worked well for photos for years now (Hot or Not?). Videos would require a lot more effort and time in comparison.
Google said that they developed this fun game in collaboration with Google Research (!).
The company added:
Earn points for predicting the crowd favorites, and see how you stack up against other players at the end of each week. Get your daily dose of the most talented, hilarious, adorable or weird videos on YouTube, and you could help uncover the next big thing.
YouTube Slam currently has categories like: Comedy, Cute, Music, Bizarre and Dance Slams.