A simple, great summary of the BIG issues with Machine Learning

The six answers you want to have about Machine Learning, all in one place. The founder of Pinboard, Maciej Cegłowski, has just published his statement about "Privacy Rights and Data Collection in a Digital Economy". The addendum on Machine Learning of that document is a great, simple explanation of its intrinsical limits, and the risks coming from them. To make them even simpler to understand, I took the liberty of synthesizing it in an easier Q&A format. Questions and parts in italic are my own additions, and any error is mine only.