Based on distributed computing technologies Google has publicly disclosed, Hadoop provides an open source implementation for other companies with very large data analysis challenges, including Yahoo! and Facebook. The free software, named for a toy elephant, now runs on some of the largest sites on the Web.
You can use Hadoop for ad hoc analysis of large data sets, or to extract, transform, and load data into a traditional data warehouse. It can also be applied to machine learning, computer modeling, and scientific computing.