Million Song Dataset Challenge
kaggle.com
kaggle.com
There are a whole lot of fun challenges ranging from predicting if a patient will be admitted to a hospital, what will be the trading price of a bond, will a student answer a test question correctly, to if a car purchased at an auction is a bad buy!
Mainly, I want to know because I suspect there is a good marketing lesson to be learned from Kaggle's success compared to seemingly similar sites.