1) Machine learning involves using algorithms to automatically find patterns in data. It is used for tasks like classification, regression, clustering, and recommendation.
2) Machine learning can help with prediction, performing time-consuming tasks, and aiding human experts. However, there are also limitations, including that correlation does not imply causation, as well as ethical and privacy concerns.
3) Popular machine learning platforms and libraries include Microsoft Azure ML, Amazon SageMaker, TensorFlow, CNTK, and ONNX for model interchange. Pre-trained models and APIs are available through services like Microsoft Cognitive Services and Amazon Rekognition.