Google has managed to come back with something very useful, indeed. It is by no means a panacea, but it does have surprisingly broad applicability. MapReduce is a framework that works by defining two simple functions: map and reduce. Someone familiar with functional programming should have a good guess as to what these do: map is a function applied to every element of a dataset, and reduce is a function that takes many elements and combines them into some smaller set of elements (usually just one element).
A short explanation of map reduce