Azure Machine Learning is another of those features of Azure I've not gotten around to playing with. Andrew Fryer of Microsoft has produced a couple of good articles on the subject, both in general and Azure specific.
Machine Learning appears to be the new marketing buzzword previously known as data mining. Given enough data, you can mine it to find gold is the basic concept. In his first article, Fryer looks at what Machine Learning (ML) is and some of the basic tasks. In the second article, Fryer looks at exploring and evaluation of the technique to see if it's of value to an organisation.