MapReduce was invented by Google in 2004, made into the Hadoop open source project by Yahoo! in 2007, and now is being used increasingly as a massively parallel data processing engine for Big Data. MapReduce allows programmers to express a transformation of data that can be executed on a cluster that may include thousands of computers operating in parallel. Hadoop is essentially the operating system that enables the program to be run on the cluster.  To read the entire article click on the following link:

http://www.forbes.com/sites/danwoods/2011/11/06/can-mapreduce-be-made-easy/