The data release, part of the company’s Webscope initiative and announced on Yahoo’s Tumblr blog, is intended for researchers to use in validating recommender systems, high-scale learning algorithms, user-behaviour modelling, collaborative filtering techniques and unsupervised learning methods.

Source: Yahoo releases massive research dataset

From: Yahoo Releases the Largest-ever Machine Learning Dataset for Researchers

Today, we are proud to announce the public release of the largest-ever machine learning dataset to the research community. The dataset stands at a massive ~110B events (13.5TB uncompressed) of anonymized user-news item interaction data, collected by recording the user-news item interactions of about 20M users from February 2015 to May 2015.