Data mining is a very popular topic nowadays. Unlike a few years ago, everything is bind with data now and we are capable of handling these kinds of large data well.
By collecting and inspecting these data, people were able to discover some patterns. Even the whole data set is a junk, there are some hidden patterns that can be extracted by combining multiple data sources to provide valuable insights.
Data mining is often combined with various sources of data including enterprise data that is secured by an organization and has privacy issues and sometimes multiple sources are integrated including third party data, customer demographics and financial data etc.