1. Hivemall is a scalable machine learning library built as a collection of Hive UDFs that allows users to perform machine learning tasks using SQL queries.
2. The document discusses why Hivemall was created, as the creator found existing frameworks like Mahout and Spark MLlib difficult to use for SQL users and not scalable. Hivemall allows machine learning tasks like training, prediction, and feature engineering to be done with SQL queries.
3. The document provides examples of how to use Hivemall for tasks like data preparation, feature engineering, model training using algorithms like logistic regression and confidence weighted classification, and prediction. It also discusses how models can be exported for real-time prediction on databases.