A nuanced discussion of software patents, this time one filed by (and granted to) Google. http://arstechnica.com/open-source/news/2010/01/googles-mapreduce-patent-wha... Hadoop is the open-source implementation of the MapReduce algorithms. I have mixed feelings on this one: - on one hand, "map" and "reduce" are as old as "divide" and "conquer" strategies in computer science. No one should be able to patent this. - on the other hand, Google's 2004 paper on MapReduce was a seminal event that unleashed the map-reduce pattern on a scale not seen before and enabled many open-source implementations (Hadoop being the most prominent). Saidi