I was curious about Hadoop, and that let me to Cassandra and DataStax and tutorials and forums--and near the end of my search I still didn't really understand whether this would be useful for me. I saw a lot of big names using it, but I didn't grasp the non-relational database concept. Then I finally read a blog entry from Arin Sarkissian that (although rather crudely written) explained the concept. And I see how and why it works--for blogs and comments, or for social networking sites, or whatever. But it won't work efficiently for my job--providing a way to track huge amounts of store inventory data and generate very quick datamining reports for customers. If I were tracking data that was less structured but more inclined to be enormous in its scope, and I needed to ensure I could keep it all and keep it intact forever, Hadoop and all the things related to it would be, perhaps, ideal.