What's the easiest way to explain What is Hadoop and Map/Reduce?
I recently found this great article describing Map Reduce :
I’ve been planning on writing about the Google’s MapReduce algorithm for some time but I couldn’t find a good practical example. Then we had a Northwest C++ Users Group presentation by Steve Yegge and a followup discussion and beers, and I had a little epiphany. Steve was talking about, among other things, the build process. And that’s just a bunch of algorithms that are perfect for explaining MapReduce.
The code examples are in C++, but the content is really language agnostic.
Here's a great tutorial on map/reduce in general, explaining the background, basics and data flow. I'm finding it useful to explain Google's App Engine implementation as well.