some links about MapReduce (不仅限分布式)
According to this link Functional Programming in C# 3.0: How Map/Reduce/Filter can Rock your World the following are the equivalent in C# under the System.Linq namespace:
map –> Enumerable.Select
reduce –> Enumerable.Aggregate
filter –> Enumerable.Where
The frozen part of the MapReduce framework is a large distributed sort. The hot spots, which the application defines, are:
an input reader
a Map function
a partition function
a compare function
a Reduce function
an output writer

Google: Cluster Computing and MapReduce

Parallel LINQ Running Queries On Multi-Core Processors

Introduction to MapReduce for .NET Developers

open-source software for reliable, scalable, distributed computing