Kaggle vs Numerai

Kaggle is an online community of data scientists and machine learning practitioners. It allows users to find and publish data sets, explore and build models in a web-based data science environment, work with other data scientists and machine learning engineers, and enter competitions to solve data science challenges.

Numerai is a blockchain-based platform that crowdsources machine learning models to predict the stock market. Data scientists build models using anonymized data from Numerai's hedge fund and compete to have their models used.