[Why the explosion in machine learning?][q] As always, major and minor reasons. Major reason? Data. Lots and lots of data, both because we human beings have put so much up ourselves, but also because businesses, and other organizations — Hello!, NSA! (Call when you’re ready to talk about how I can help!) — have collected so much. And that’s the minor reason right there, if one can consider it minor: organizations want to “learn” things from all this data.