Recommender systems are found in a wide range of internet applications. They are designed to help reduce information overload and to guide users into selecting the most suitable options for them. Amazon, for example, provides personalised recommendations for new products, using data about users’ previous searches and purchases. After selecting an item, the customer is presented with further suggestions for products that are ‘frequently bought together’ with the one being considered, thus drawing on the data of other customers as well. Social networking platforms use information about their users to recommend people they might want to connect with, while media providers such as Spotify and Netflix suggest content to their users, based on what they and their friends have already listened to or watched.