4 great leaps machine learning made in 2015

Until recently, machine learning was an esoteric discipline, used only by a few who understood the algorithms and had access to tons of data on which to employ it. But with big data technology becoming a commodity and algorithms easier to use, machine learning has moved out of the shadows and into the hands of citizen developers and regular users. Here are four key steps to that development during the course of 2015. "Easier" is a relative term, but anything that simplifies the amount of work needed to get useful results from the intrinsic complexity of machine learning is a boon. Spark, the in-memory big-data processing toolkit, simplified machine learning with its relatively straightforward programming model -- available to more than Java users alone -- and its built-in array of machine learning algorithms.