This document discusses using machine learning and data mining techniques to gain knowledge from big data. It defines key terms like data, databases, and big data. It explains that machine learning and data mining can help solve the problem of "data overloading" by discovering patterns and making predictions. The document also introduces social network analysis and crowdsourcing as collective intelligence approaches for learning from data. It provides examples like Amazon Mechanical Turk, which utilizes crowdsourcing for various tasks.