In online learning, data is constantly being streamed into the model and is used to update the model. The model is learning ‘online’ meaning it is continuously learning as data is fed through. An example of an online learning model is Netflix’s recommendation system. As you provide feedback on which shows you enjoy, these data points are fed into the model. The model learns something new and your new recommendations are more relevant. Online learning is typically used for systems where there is a continuous flow of data and the model needs to be sensitive enough to adapt to changing conditions.